Once you start down the restoration route its hard to control the spending, it is very satisfying but will take all your time and money,where as a quick tidy up and get it running would be easier on time and money it is really not realistic on something that has sat 35 years, all the wheel bearings and steering bearings would need doing , new tyres, probably cables ,fork oil and oil seals and recommissioning the engine, and a whole heap of other things that would come aparent as you go through it, try and load up some pictures
I would think a decent restoration is going to cost anywhere between $5,000 and $20,00, depending on how much work you do yourself,
A Vic World restored sandcast sells for around $32,000 acording to his web site
Pete