You are probably basing this on the old Rowa 10-6, which is a really nice car.
I used Microtrains trucks on mine, which are a little undersized (and have 33" wheels) but work very nicely with this car.
Spookshow has a nice gallery of N scale trucks here :
http://www.spookshow.net/trucks/trucks.php Scroll down to the section that says "Four-Wheel Passenger Car Trucks (late)"
Then look at styles like GCS 41-N. Some are nice, some are awful (like Model Power). Some are very nice - I think the Rapido and Walthers trucks are the nicest. The Rapido truck as a low bolster, so you'll need some extra washers or some such. Kato has a style GSC 41-CS-11 that is close enough and very nice.
If you don't use the Microtrains truck, you might still want to use the mounting boss they provide to adapt the really large hole in the floor of the Rowa car to something that takes a more normal pin or screw to mount.