Exploring Nizhny Novgorod in a Rikshah might be a good way to see the city for elderly or handicpped people, because these vehicles will be able to get to almost any place of the city, although I saw them driving up and down the pedestrian zone in Bolschaja Pokrowskaja only.
It will be quite hard to rent a wheelchair when you are a tourist in Nizhny Novgorod and this might be a good solution for your transportations !
I came to Nizhny Novgorod by cruise-ship, on a rivercruise from Perm to Moscow, onboard of M/S Furmanov. Such tours from or to Perm are not yet offered very often, in fact it was the 1st cruise of the summerseason in early May 2008 and that same cruise will be done again as the last cruise of the season in October, before the ship will be taken to Rostov na Donu.
Cruising these rivers is a great way to see the russian countryside far away from Moscow and St. Petersburg and you will get to places that you will hardly be able to see any other way.
For a cruise of 11 days I payed 2400 euros in the singlecabin, all transfers and flights from Vienna to Perm and home again from Moscow were included in that price. That same cabin is just 1700 euros, when you book in Germany and fly from Berlin.
This might be interesting for you to know, when you travel with your smaller children. It seems to be quite popular among the local population to take a ride on a horseback through the pedestrian zone . I had been there in beginning of May, when it was warm enough already in the area.
One can get to NN by different means:
1) by car
2) by train (if you take it from Moscow, while bying the tickes please mind that the direction is still named "Gorky")
3) by air (NN has an international airport, check your local carriers; if you fly from Moscow, take Aeroflot from Sheremetievo 1)
Be aware, if you are traveling here from Moscow by train, you should by tickets to GORKY. For some strange reason the city is not listed by it's "new" name but by its Soviet name at the Moscow train station.
By train from Moscow, a couple of trains and rather convenient schedule. It takes 5 hours to get there from Moscow Kazansky Railway station.
By taxi, which is 40 rubles around the city to any direction. There are very good and reliable official taxi services, one of them is 44-444, and has the same telephone. Cheaper than gipsy taxies (unofficial ones, who may charge you twice more) - different than in Moscow, where unofficial once are usually cheaper. The taxis usually wait at the hotel and railway station. Also, you can use city buses, which are 2.5 Rubles per ride.
by plane from moscow of course;
but there is a night train coming from moscow,very slow,12 hours for 500 kms,and the same train to go back;
trains are very cheap in russia,it is a good tip to sleep in trains so you do not have to pay hotels
Sometimes (at big holidays) one can take a helicopter trip around Volga river and see Kremlin of N.N. from birds view.