We've put an antique bathtub (not original to the house) into two different bathroom projects. Both times, the beautiful tub was the feature in the room that brought everything together and made it really neat! The first time, we found an old tub through a salvage company. The second time, it was off craigslist. Look for a tub that has the original enamel finish on the inside in decent condition, so that you don't need to refinish it. The original finish is more durable and way cheaper than refinishing.
With ours, we sanded the exterior outside, primed, and painted. First time black, which looked great. For the house we're in now, we did a deep red. The first time I bought a shower ring, we went cheap and regretted it every day. When we finally redid the bathroom right, we bought a very nice spigot with shower head and ring in one package that was WAY sturdier and better looking. So, don't skimp there. I've never been too crazy about the shower ring, though, so this time we put a stand-up shower and the clawfoot tub in with just a spigot. We use it for bathing our kids and the occasional adult bath.
I never thought it was really difficult to clean under - just ran my vacuum under there every once in a while. Good luck!
