For mainly Croom riding you'd probably be happier on a four stroke, but any that you'll find in your price range are likely to be more trail oriented than the current crop of 4 stroke racers. Not necessarily a bad thing, but it will be heavier. You could definitely pick up an older two stroke dirtbike in that price range. I think I paid like $1300 for my 91(3) Honda CR250.

A two stroke at Croom is okay but you'll want to carry extra spark plugs for the trail riding. Fouling plugs is pretty common unless you adjust your carb pretty regularly for temperature changes and such.

YMMV