If you want a good cycling tour of the city, you might enjoy riding from all the way from one side to the other. Note that the easiest and safest way of enteriong downtown or Canal Park from West Duluth (or vice versa) is via the pedestrian / cyclist bridge and path. The entrance is in the West End on Superior Street after the M & H gas station and just before the road takes a freeway-like form. Ride through the chicken-wire tunnel and take the first turn (at the end is a staircase!). This leads to a small little park-like area under the freeway where you are given the option of exiting to downtown or Canal Park. The downtown exit goes to Michigan Street just below the library area. The Canal Park exit brings you somewhere near the Great Lakes Aquarium.
Getting down the hill is fun (but be safe, especially if you choose "Horseshoe Bend", e.g. Haines Rd. / N 40th Ave W!)...getting up it isn't...well, maybe for sado-masochists. If you wish to get up the hill on your own power, the easiest way up seems to be Highland St. out of West Duluth to Proctor. This, however, will bring you to a completely different area than the Mall Area, Piedmont, etc. To get up the hill there, you'll either want to walk your bike (unless you are very fit) or, to cheat somewhat....
Put it on the DTA bus rack!
Many, most, or all of the local DTA buses have a bike rack on which you can mount your bike. This is a tremendous help if you wish to get up the hill.
Although you will probably arrive by car, from May to September, you may certainly want to bring your bike. Duluth's older neighborhoods are best explored on two foot-powered wheels, in my opinion, plus friendly drivers (in my experience) and a decent network of bike paths make the city very fun to bike around.
The Westside Waterfront Trail in West Duluth is a nice path for walking or bicycling (a bit narrow) and follows the St. Louis River. You enter on 74th Ave. W. near the zoo (per the city's official website, but it seemed to me that it starts a bit earlier a now, although I'm probably wrong) and follow to Riverside, about a five mile path. Free parking.
Canal Park's own Lakewalk (mentioned in a seperate tip) has a paved path of decent width for cyclists and rollerbladers.
The Munger Trail is a paved path linking Duluth to Hinckley, MN, a seventy-mile stretch. Note that leaving Duluth proper requires quite an ascent (about 600 feet), but the grade is not that bad here, just long. Riders not wishing to make the full ride will take great pleasure in riding to the small twon of Carlton and back, about twenty miles each way. This is probably the most scenic part of the trail anyway. From Carlton the larger city of Cloquet (about 12,000) is about a twenty minute bike ride up the highway. Free parking.
See the provided website for more info.
The vast majority of visitors to Duluth drive in, and you'll probably want a car, or suffer limited mobility. This is because 1) the "international" airport is very limited in terms of regular passenger flights, only to and from DTW (Detroit) and MSP (Minneapolis-St. Paul), and 2), as in most American cities, Duluthians tend to rely on their personal vehicles, and the newer parts of the city and use of public transportation reflect that. The city is also very steep - that could be an advantage, as it would be a great opportunity for the mountain biker to test himself, and even the walker would get quite a hike coming up from near the shore to the top of the hill.
Duluth does indeed have a bus system, the DTA, which works quite well, but might be confusing to some visitors and is not a very fast way of getting around (except perhaps from downtown).
See "walking" and "biking" for information on those subjects.
It's really helpful to have a car when visiting Northern Minnesota. There is a lot of beautiful country to see up here, but it's not accessible by public transportation. I was talking with my mom's uncle the other day who doesn't drive at all. He told me that he used to visit Duluth (from Minneapolis) all the time. He would take the bus, which is still possilbe, although the bus no longer makes any stops in between the Twin Citeis and Duluth. However, once you arrive, you'll need a car.
We took a long morning walk on Duluth's extensive Skywalk System, which interconnects most of the downtown area. These walkways are on several levels, and some actually lead through the lobby areas of restaurants, banks and businesses. the longest section crosses over Interstate 35, connecting the Duluth Entertainment Convention Center and the lakefront area with downtown. The 18,000 people who work in downtown Duluth, and the many more who visit there annually, can walk almost anywhere in the downtown area without going out of doors . Parking garages and spaces next to the skywalk can accomodate almost 14,000 vehicles. This can be very helpful in a city which has some of the harshest winter weather in the United States.
Duluth has a transit system, however, the city is much better suited to those with a vehicle. I have had pretty good luck on the city buses, they are clean, drivers are friendly, however, certain parts of the city (London Road) are not on a bus route. www.duluthtransit.com.
The Greyhound Bus Depot is in the western edge of the city, and there are 3 buses a day to and from Minneapolis, and a ticket is about 20 bucks one way.
Taxicabs are okay, but, since a lot of places are very far off the beaten path (mall, airport, bus depot), and the city is very long, a cab ride can cost you over 20 dollars to get someplace.
Ever want to know what your gerbil feels like?
The skywalk system is a great way to get around downtown Duluth and kind of fun. There are a few skywalks that can get you a nice city view, as well.
While technically not a part of the public skywalk system, I especially recommend the skywalk between St. Mary's Hospital and the Miller Dwan Medical Center that crosses 2nd Street around 5th Avenue East. You get an amazing view of the lake, the lift bridge and the downtown area and there are nice benches to sit on. Get a sandwich and enjoy the view.
Duluth is very easy to get too as it is right on Interstate 35. It is only 150 miles north of the twin cities so with the 70 mph speed limit, it is only a little over two hours from Minneapolis/St. Paul. There is no view better than arriving in Duluth on Thompson Hill and seeing the harbor and city below! And because of Lake Superior, Duluth has natural air conditioning so you will probably be able to turn your vehicles ac off!
You can drive here up I-35 or fly to Duluth Int'l AP (usually through MSP/Minneapolis).
If you really want to explore the entire city (and perhaps areas outside of it), even the sections most tourists neglige, then it may be advisable to rent or drive your own car. We have OK public transportation, including a trolley-like tourist bus. A motorhome is always nice, as it is anywhere. Duluth is a cool place to motorcycle to in the summer, but only in the summer, and it's also a great place to bike, but only in the summer also (due to the cold).
I have always driven from home (IA) or from our cabin in nearby Grand Rapids(MN). If you were to fly I would suggest flying into the Twin Cities to avoid higher ticket prices. If you want pay huge $$ you can cruise into town on one of the ore or grain ships.
There is a public bus line but I am unsure about is range in the city. Biking around town is a good time but beware of the incredibly steep hills. Driving and walking are probably you best way to get around.
I-35 is a straight shot up to Duluth from the Twin Cities. It's an easy drive, takes about 2 1/2 hours to get there.