Since Guadalajara is only about 6 hours from DF and it's expensive to fly five people around, we drove. This was our first longer trip in Mexico.
The tolls were about $120 round trip. There are plenty of libre roads, but they're much slower. We could usually go 110 kph on the toll roads and they were well-maintained. We did run into a little trouble at the end when we were short on cash and the gas station couldn't accept a credit card payment over 500 pesos ($40), but we scrounged up a few more pesos from everyone in the family and made it home with 20 pesos to spare from the week's budget.
There are, not surprisingly, lots of people walking along the sides of the roads. That was a little unnerving when you're going 70 mph. There are also lots of SOS phones, but half are on the wrong side of the road, so if you can, keep going to the next one so you don't have to cross 4-6 lanes of traffic.
We also got to see the Green Angels for the first time, although we didn't need them. They're Mexico's roadside assistance system on the national roads, toll or libre. You can call them from the SOS phones or your cell, or wait for one to drive by. They'll do anything they can to fix your car, give you a liter of gas, push you over the hill, or whatever. I even have heard they have medical training. The service is free, but of course you'd tip anyone well who saved you on the road.
There were plenty of places to stop and eat or to get gas. I felt like there were more options than along US toll roads.
There's more to post- specifically about Queretaro and bike pilgrimages- but I'll do those later.