Check out the Bearing races on the hubs - if you think they are OK and the cassette body works, should be ok - get some spokes and rims - hubs can last quite a while longer than the rims in most cases - the cassette body might be difficult to replace if its not working.
I took some terrible rims off a pair of really well preserved hubs a while ago and rebuilt they are still running strong, much happiness in building your own wheels
Prob best to replace the spokes, they aren't that expensive in the scheme of things and unless they were installed well, they may be seized and so on, they will rarely be the same size also.
p.s. Good reading material: http://www.wheelpro.co.uk/wheelbuilding/book.php