wow, tough spot. first, no hasty decisions. nothing good ever comes from being in a hurry. $21K is a lot of cash so I think a 2nd opinion is in order, preferably from a qualified shop in that same town. locate one and have the RV towed there. you don't say how old this MH is but if the news is the same, more or less, you have to then do the math. are you making payments or do you own it outright? do you want to be $21K in debt or can you pay cash for the repairs? is that all that's wrong or is another Murphy episode waiting in the wings?
give it some thought and go from there. good luck.