Well I think your question is more related to getting in and out of stations and have been answered completely.
What I would add is both don't trust your Guage when it says 1/2 full until you have verified that is the case with your MH.
I would say make a good determination of your gas mileage and you will know how many miles you can travel based on the gallons of gas your tank holds leaving room for the fact that you can't draw every drop out.
Since I have determined my mileage I will many times run down to 1/4 tank, my tank holds 75 gallons so at 1/4 I have 18 3/4 gallons at 7 miles per gallon I can travel 131 miles, I feel I can probably find gas in 131 miles.
Also remember that if you use the genny you have to take that into account.
Lastly I keep a empty 2 1/2 gallon gas can on board you can keep it on MH or truck of toad at least you can go get some if you try to push how far you can go ( like I do )