I'll take a first crack at this. This is a pretty broad question - and much the information you're seeking depends on your experience level with older sailboats. How much background in older boats do you have?
With a vintage production boat, the issues are mostly typical for that age. You can start with the rigging, both if it's original to the boat, and if not when it was replaced and with what. You would want to check the penetrations of the deck by the for leakage and the deck itself for moisture. You'll want to run the chain plates down to their anchorages to check their condition. Also look at the bulkheads and their attachment there.
E35-3s typically have some moisture in their coach house roofs because the dorade vent forward of the mast. In a boat of that vintage you'll commonly find leaks originating at box (most owners close up the center compartment with teak or other). The presence of moisture is in itself not necessarily a deal killer (it all depends). Do some searches on deck moisture and you'll find lots of threads on the topic. The anchor locker has a similar condition and is typically rebuilt by this point.
Also - have you had a chance to look at some of the similar threads on E35-3s and E38s, and have you reviewed any of the E35 documents in the archive?
I'm going to move this thread to the Design & Function forum as that is typically where these types of questions are found.
//sse