Ive only done drywall repair not tape/mud an entire area like this. I can skim coat great, lots of practice with that on the last house we rehabed.
I figure I"m still saving money I have to do it.
This $5000 investment is netting me a return of nearly $40K in increased value. Its worth the suffering, and the reward of the kids having a place to go and keeping the noise away from parents, priceless ....