You should also consider what you hope to get out of the trip -- by this I mean: what will you have when you get home?
My experience with a 3-week all-inclusive tour of Europe was that when I got home I felt like I saw Europe as a series of postcards...stopped here, took a picture, got back on the bus; stopped there, took a picture, got back on the bus... Most mornings we had to get up early & have our bags outside our door by 6:00. And, the time spent in some cities was very early before anything was open (or late after things had closed)...because we had to make tracks for the next destination, or got into town late and had to leave early the next morning. Yes, people were grumpy -- there were some very nice people, but some weren't so nice & they weren't all Americans either. Some hotels were nice, some weren't so nice. Some restaurants were good, some weren't, but we didn't have much choice, or opportunity to try things on our own.
My next experience, about 16 years later -- we did it on our own. My Mom, who was about 71 at the time & I (40-something), planned a 5-week trip to England & France. We rented cars and stayed in B&B's. We studied before-hand and knew what we wanted to see & do. Most importantly, we found our own "backdoors" -- places that excited us and felt special, like they were there just for us. And, when we came home, we had rich memories that have lasted to this day -- 16 years and 3 trips later!
We used Rick Steves' books as our guides, but tailored to our own needs -- we want a private bathroom, if you please!
If you do decide to do an all-inclusive tour, make sure it is a good one and do your homework before you leave -- do research on the places the tour visits, so you will know what is there and can make best use of your time at each destination.
Good luck! And, Bon voyage!