A small market town to the south of Northallerton and easily reached by train and bus (regular services) I must to been slightly disappointed by Thirsk - a pleasant enough place built around a large square but with very little for the visitor apart from the James Herriott Museum (which we did not have time to visit).
Brompton is a pleasant village about 2 miles east of Northallerton that is worth an hours visit to walk through. A very old village that has buildings dating back to the 1700s it has large grassed areas on each side of the river (Brompton Beck) that runs through the far eastern end of the village towards a weir.
It was also a focus for much conflict between the English and the Scots, most notably the Battle of the Standard,in 1138, which saw losses of as many as 12,000 men. The Scots were repelled here safeguarding the whole of the north of England from the Scots.
The village has one hotel and three pubs with also a local shop and is served by a frequent bus service from Northallerton.
Buses between Northallerton and Brompton seem to be fairly frequent and the details are here - http://www.northyorkstravel.info/place/brompton/
Masham is a wonderful old town set around a large market square - there are markets here on Wednesday and Saturdays.
There are two breweries here - The Black Sheep Brewery and Theakstons Brewery and both have visitor centres and brewery tours.
The market place is by far the largest in the district. It is tightly bordered on its south and west sides by ranges of old two and three storey buildings. To the south-east, lies St Mary's Church with its large churchyard.
Masham can be reached by bus from Northallerton (see http://www.traveldales.org.uk/starting_points_bus_item.cfm?itemID=16). Bus 73 to Leeming Bar and Bedale for connecting bus 156/157 to Leyburn (weekday connection with bus 159 for Middleham, Masham).
Recommended and see my full Masham pages here on VT for more information.
Markenfield Hall in North Yorkshire will be open to visitors on just less than 30 days in 2010. This is a romantic house built in 1310 and still completely moated and stands at the end of a mile long winding drive.
South of Northallerton on the A61 south of Ripon. The entrance to the drive is between two low stone walls bearing a dark green sign saying Markenfield Hall.
Entrance fee is £4 and concessions are £3.
Market town on the River Swale with a castle standing high over the town. Good variety of local pubs and country craft shops as well as some interesting eating places. Cobbled streets and wonderful vistas to hilly countryside that surrounds the town. Rather hilly in places but the centre around the largest market square I have ever seen is flat.
There are several pages here on VT should you wish to know more.
A short drive west from Northallerton or a bus journey by local bus.
Stokesley is a small town to the east of Northallerton that is pleasant to visit. A very simlar town to Northallerton but much smaller in size. There is a direct bus service.