Never had a CG tell me I couldn't keep my dolly onsite or charge me extra for it. Most places I don't have any issue with leaving it connected to the MH. If the site is short, then I can usually just unhitch and slide it forward with the tongue of the dolly up under the MH. At home, I have set up my lawn tractor so that I can hiitch the dolly to it to move it around the yard to its storage spot. That is the biggest hassle of having a dolly.
Next vehicle will be 4 down. I feel that would be the better way to go, but if a dolly is what you have it isn't the end of the world. You will need something to help you move it around your yard. Put a hitch on your lawn tractor if you have one, or Harbor Freight sella a "Trailer Dolly" which would simplify moving the tow dolly manually.