Congratulations Hoodoo. It looks like a clean car and a great buy. And your story is very similar to my own. In fact I knew your problem as soon as I read petal was spongy.
We (my 12 yr old son was with me) were lucky that when my M/S cylinder went out, I was able to limp the car into an Acura Dealer in Louisville, KY, that had an NSX tech. It was the same problem, the car sat for a little too long under the previous owner. Anyway, they ordered one from Honda in California and tried to have it overnighted but, the plane had to make an emergency landing for whatever reason and I would be stuck in Louisville for the weekend. No problem though, because the dealer treated me like I had bought the car from them. They helped me with a hotel and gave me a loaner Acura TL and said go explore Kentucky. So, we did. Toured the Louisville Slugger factory, drove down to Bowling Green and toured the Corvette Museum and factory, etc. Then, when I picked up the car, it was washed and we were greeted by some of the local NSX owners who found out about the car being there. What was a stressful ordeal turned into a great adventure for my son and I to share.
I think you made the right decision to drive it back. I have owned two NSXs and drove both home from over 1000 miles away. It's a great adventure, an extremely cool way to travel the country and it's the best way to get to know your car. On both occasions I made a list of things that I wanted to address. Mostly minor squeaks and rattles and maybe some things that needed updated. Now my Orange Unicorn gets driven on weekends, goes on one or two trips over 1000 miles (NSXPOs and to the Florida Keys) every year and to the track for the NSXPO HPDE. I highly recommend going to the NSXPOs. You will be surprised at how tight knit this NSX community is and will make some life long friends. Drive that car and enjoy it. You have some of the best roads in which to enjoy your NSX in the country, I'm jealous.