Cheeki:

1. I'd budget several thousand dollars even if you do the labor.

2. Yes.

3. The dining room wall is exterior, that makes it load bearing. It isn't particularly difficult to frame for a window in a load-bearing wall, but you've got to know what you're doing.

4. Yes, probably.

Cheeki, I hope you don't mind my saying so, but from the nature of your questions, this sounds like a project that's well out of your league. I'd suggest you contact a remodeling professional with an excellent reputation.

Thank you for your response Trebruchet. We are leaning towards hiring a professional. I am trying to get info on how much work might be involved, what are the pitfalls of this much work and obviously, a monetary estimate for the work.

Be prepared for sticker shock. Several contractors we know have told us they do a lot of bids for decks and porches, but do very few actual projects like these because the cost is soooo much higher than the homeowners anticipate.

Having done a covered back porch ourselves, I can attest to the fact that there are a huge number of expenses that aren't readily aparent when you first consider taking on the project.

Takeaway: won't be cheap, but will provide lots of enjoyment once completed.