Before closing the door on needing to sell yours, do you use a credit union? i ask because hubby and I plan on buying before we sell. We'll do a 2 year ARM, with 5% down, no PMI. Then, when we sell, we'll refi into a 15 or 20 fixed. This way we don't have "the contingency on sale" getting in our way and we can actually afford the two payments. We actually almost bought a house and we won out over another couple because we put in a noncontingent offer.
before closing that door, talk to a good mortgage guy and figure out what you can really do. I had no idea how easy it was to buy a second home., if you have assets (which I assume you do because you're frugal and hardworking), you'll be surprised by what they will allow and what you can do with a cheap ARM. When you sell, you then refi into a 20 or 30 fixed. It's something to seriously think about.
If I was you, I'd talk to the woman ASAP. I'd then find a credit union and get approved to buy noncontingent. I'd then find a lawyer (but I think you are one, so you probably can skip that since you get the whole devils in the details thing). But really, tell her and find a mortgage guy. But mostly, talk to her, go see it, and see if it's a fit. Then go from there. You may hate it. I've seen lots of homes that sound amazing, but really, they are terrible. Bigger isn't always better. Go feel the floor plan. I have a good friend in a studio in Vancouver that had a chance to move into a 1 bedroom. She realized her great california closet additions, etc. made the bigger place look pathetic.
GOOD LUCK.