The general consensus among those who post here regularly is that guided tours are for loosers and wimps. Ok, not really - but everytime somebody comes here and asks "guided or do-it-yourself" roughly 80% of those replying will say "do-it-yourself".
This is just to tell you how most of us regulars here feel about the subject, not a dismissal of guided tours in general. If you like guided tours it is fine, nobody is going to look down on you.
But the chances of finding somebody here who has gone on a guided tour are not that good.
At the very best you'll find somebody who went on a short daytrip from a city such as Florence for a trip to some wineyards plus sightseeing. Usually the best way to get to wineyards is to drive your own car - but difficult if you are alone and want to taste the wine too. Thus some might opt for tours.
BTW, in Germany (and Austria and Hungary too) you can cycle in wine-growing areas without being a crazy biker. You need to be reasonably fit in general, but many of the pathways are smooth asphalt and manageable even for the 60+ plus crowd. Essentially you follow rivers along their course, thus it is mostly flat. With a tent and your own bike this is a very cheap way to travel too. The Rhine River south of Frankfurt or the Mosel River would be good choices. http://www.rheinradweg.eu/en/