To be honest have never seen the majority of the signs above and we have traveled around the USA a fair amount. Most advisory signs will be in Blue, a camper trailer with a pipe down indicates that there is a dump station. Most other signs will just be written out for ya. Brown ones normally found in the towns/cities. But if you see a sign with a trailer (most common I think) it will be indicating its something RV related, camp ground etc.
Rules of the road is to 1. first and foremost know the rules of the road for driving itself. 2. Do not impeded the flow of traffic, you are not to self impose speed limits you might like on others. 3. Stay right or toward the slow lanes if not doing the speed limit. 4. Have some courtesy for others as you would like them to have some for you. Used to be folks would pull over to allow vehicles behind them to go by if they were holding up traffic. Now they just ignore the ones behind them it seems. I would also recommend the possiblity of having a CB radio. You dont know how many times I have seen problems with RVs and you cannot get the driver/passenger attention. Put the squelch up and volume down to just being audible and listen for close signals they could be trying to tell ya something. There was an article some years back about a guy pulling a towd and he ignored the horns etc behind him. He said he just thought folks PO'd because he was holding up traffic. Turns out he had a flat tire on the towd and the tire was worn away and the wheel was sparking on the highway. Cost him I think around $200000 for causing a forest fire!
Watch your reaview mirrors and be aware of where you are all the time.