1. You can borrow for up to the appraisal amount. If it does appraise for more, they do allow you to get bids from contractors or estimates from a hardware store (if you're able to to the job yourself - I was told specifically that things like plumbing and electric cannot be done yourself) to do the repair work or to do things like replace the flooring or counter tops. There may be some repairs that USDA requires you to do in order to get the loan. We are doing this loan too, and the house we were looking at before needed the roof replaced, and that was a required repair. If it didn't appraise for enough, then we'd have to repair that out of our own pocket or negotiate with the seller.
One thing I want to mention is the lead paint issue. My USDA office made a really big issue about this when we did the home inspection for the house we were going to buy (that has fallen through so we are no longer buying it). They said to make sure there is no peeling or cracking paint when they do their own assessment otherwise they have to do some sort of invasive lead based paint test. If you do any sort of repairs that disturb the paint, they will require a lead based paint test. I was told this is expensive and time consuming.
2. I do not have any experience in that department because I'm still looking for a house with this loan. I think once you receive your eligibility letter and if your financial and credit situation remains unchanged from when you applied, then you do not have anything to worry about. Just don't go out and apply for a bunch of credit, or finance a car or some other large purchase from now until after you close on your loan, because USDA told me they have had to ultimately deny someone at the last minute because of something like that.
Hope this helps! Good luck in your journeys!
The adjacent county may still be served by the USDA office you applied with, you should contact your USDA area specialist and ask. A lot of USDA Rural Development centers cover several counties.
You can normally find what offices cover a county by going to http://offices.sc.egov.usda.gov/locator/app?1=1 and click on the state, then click on the county, and a "Service Centers in Your County" will appear with 1 or 2 locations, and in that same small box at the bottom it'll list the services that location provides, if the office does the USDA Rural Development loans (Direct or Guaranteed) it'll say "Rural Development" on it. If not, there will be another section right below called "Service Centers in Other Counties" and it'll always (as far as I've tried) list one with a Rural Development service center if the one in your county does not.
It just might matter.
While their offices may work with-in additional counties this is not always the case. You would be best to ask them directly.
Hope they do, but unless we know where you are considering, only the office can tell you.