I go to Mexico almost every year (some years more than once). Some times on the bike, sometimes with the family, sometimes I ride my bike and meet my family there. I am no fan of organized tours of any kind, so I can't say if they are still as good as you remember. What I can tell you is that traveling in Mexico on your own is trivial. Yes, it takes a bit more planning, but that is a big part of the fun of going on a trip. You also end up learning more about the places you go through that way.
If you have any question relating to places to visit in Mexico (as part of a tour or on your own), I'll be happy to help.
Gustavo