for the money, the thrush is a decent option and you'll probably be happy with it
for 16, you sound pretty informed and knowledgeable.
obviously, you can do the pcv valve yourself. its a 30 second fix.
the cover gasket is an easy one too. there pleanty of threads on it too. here's my thread back when i did mine. very easy to do.
as far as the carb goes, thats kind of a fun one if you ask me. it costs $20 for the rebuild kit from any parts store + a can of carb cleaner and a roll of paper towels and an old toothbrush.
again, lots of info and tricks/tips on this as well.
just get a radio, decent size table or cardboard boxes on the floor and start taking it apart while taking LOTS of pics along the way. do it outside in the sun so your well ventilated too. should take you 1-2 hours and you'll be proud of what you've accomplished.