For the single day 75-100 miles, you just need a wallet and any bag to carry the items you need for a single day ride. For the two day trips, its a pretty light load and I would expect it to be less than 20 lbs of gear.

Back in the 70's I toured on a road bike and just put a rack on it and added a large range RD and wide range freewheel. I used this setup for years.

Its always fun to get a new bike but if you are new to touring, add a rack to your current bike, go on a few tours and decide if you like doing this before the expense of a new bike. I setup my touring bike a couple of years ago and now i am doing more credit card touring, and use my road bikes.