First of all; Welcome to Sailnet. - don't be afraid, we don't bite (hard).
1) what is the problem with buying a boat that's been on the dry for a long time? I know there are a lot of seals and stuff that can break down, but I'm thinking structurally. I can repair just about anything (my other hobby is woodworking) but I do understand there comes a point where fixing something is just not worth it. I understand the cost vs value issue. That's why I'm looking at structural issues and such.
Usually, boats that have been on the hard for an extended period of time are neglected. The surest way to ruin a piece of complex machinery is to let it sit unused for a long time. Small problems that could have been quickly addressed, turn to big problems, and eventually reach the point of no return.
2) What issues to look for on a boat? I know to look at the hull integrity, keel damage, rudder issues, chain plates and and soft spots in the deck etc. But what kind of things are really deal killer type things? Like some soft spots may not be as bad as others, right?
Hull to deck joint, hull to keel joint, transom, rudder post, overall mechanical condition. these are all things that could kill a deal for me. Although, when I had my boat surveyed, the keel was falling off
. After the PO fixed it, I bought the boat.
3) inboard vs outboard? Pros and cons? Is there a rule of thumb of some sort on the size of the motor to the size of the boat? Diesel or gas? Does it really matter or is it a tree hugger personal preference thing?
Outboard = easy to fix, and easy to replace if you cannot fix. Outboard also (usually) = gasoline (explosive).
Inboard = bigger boat (>27 feet), harder and more costly to fix unless you DIY (mechanic comes to the boat)
You need a motor that is powerful enough to get the boat from 0 to hull speed in about 2 min.
4) Any specific features to look for?
Look for the boat that you and your wife
agree will suit your needs & budget.
Also - I suggest that you pay CASH.
I was where you are in 2007... I now own a 35' sailboat with an inboard, and I have rebuilt just about every system on the boat. It is costing me a LOT more than I though, but I am getting a lot more out of it than I planned.