Have you been to Bonampak?

I have been to Bonampak and Palenque. The roads are fine - a bit twisty and lots of ups and downs and just one lane each direction. If you get on a hill behind a truck or bus with bad exhaust that can be uncomfortable waiting for your chance to pass but it is not anything to put you off your trip.

If you want to get an idea - have you ever used Google street view? You can check out the main highways on google street view for yourself. You will see that the main roads are all clear, paved and in generally good repair.

When I was at Bonampak about five years ago you needed to park outside the ruins and pay the local Lacandon Maya to taxi you into the site.

Not sure how much it rains there at that time of year, we were there in November.

Enjoy your trip! Try to fit in the ruins at Toniná & Yaxchilán too.

Edit - Ken your 100% anti-Mexico posts are not helpful to anyone - go away.

Not without a tank