Brownsville to Tulum

Hey all, we are thinking of traveling from Brownsville to Tulum in June of this year. We have been to Tulum, but have flown in. We have a 2002 fifth wheel and a 2001 silverado diesel truck. I am concerned for a few things. 1. The saftey on the roads and the cities along the route. 2. What is the best route to take and how are the roads. 3. What type of truck/rv insurance do we need. 4. How important is it to speak spanish, can we get by with just english. 5. Any suggestions, ideas, things we should think about maybe traveling with a caravan. Thanks for any and all comments!!