$7k sounds rather excessive to me, unless the rot damage is significant. Anything more than superficial rot should be pretty easy to detect by walking or crawling around the roof and seeing where it's soft.
If you're somewhat handy and have the time and a helper or two, you could do the work yourself for a lot less than that; the roofing materials should be less than $1k, I believe. In any case, while I won't tell you what to do, I will say that were I in your position I would at the least get a second or third opinion/quote if possible.