You really don't have to worry about the total weight of the dolly, just the tongue weight.
Can you lift the tongue weight and then push it around?
Our Acme (cartowdolly.com) has a tongue weight of around 50 lbs which I can move around pretty easily.
When arriving at a campground we'll unload the car somewhere near the office prior to driving to the campsite. At the campsite I'll pull the RV up past the site (which I would do anyway to back in), unhitch the dolly and walk it back to the rear of the site (to about where I want the RV's back end to be). Then I'll back the RV in over the dolly so that it is mostly covered by the rear overhang of the RV.
If the site is long enough I just leave the dolly hitched up but then our RV is only 25ft long. You're likely to be longer LOL.
You can see here I have the dolly tucked under the RV:
I also have a hitch lock on the dolly so it doesn't sprout legs and walk.