Good work!!!
Preparation is really the key to making a long ride comfortable. It took me a long time to get this. Lots of pain and suffering but I finally got it. In fact I'm just now starting to use chamois cream to help prevent the saddle sore/rash thing that can happen on real long rides. Food and drink is essential.
Longest I ever did fixed was about 75 miles, but it was a tough hilly route. 100 miles flat (no headwind) would have been a bit easier I think. But it's really great to put in long miles like that fixed if you can.