T.F.
My husband used poison for years to control the rats before I moved in. I tried it and thought it was stupid. I went out and got some wild kitties and tamed them. There are tons of feral kitties in vegas due to people moving out of apartments and just leaving their cats behind to fend for themselves. I suggest you go and get two and I can guarantee that your rat troubles will be over. You can close off and exterminate as much as you want but they will always come back unless you make them not want to be there.
As for the insulation we hired some boys to get it out for 10$ an hour. We bought them masks and gloves and grab it tools for the tough parts, and a few rolls of big heavy duty trash bags. We at this time do not have insulation but I am now in san diego and it is not as big of a deal. I suggest the spray on insulation that goes on the ceiling it is costly but it will save you a ton on your air conditioning bill. I have a friend on russle and the 215 that did this and it cut her power bill in half just make sure you get closed cell foam.
Good luck.
T.