I did both Summer Tour (in Michigan) and Shoreline (west), years ago. As I recall, most of the riders were not really strong. If you get into a big tour with fit cyclists (like DALMAC), then you get monster pacelines. Even if you ride solo, you will probably collect a tail.

I have done Vermont Bicycle Tours a number of times but that was years ago. I always did tours in their "challenging" category and they don't have those anymore.

I did a couple of Cycle America Tours. Those were in the western national parks and were quite good.

More recently, I have been getting my multiday tour fix with the Florida Bicycle Safari. It is a camping tour and spends 3 nights in Live Oak FL and 3 nights in Cherry Lake FL and goes off in April. The roads up there have light traffic and amazingly courteous drivers (at least as far as FL is concerned, here in Central FL, cyclists seem to be regarded as vermin).