Help with parking area

We park our TT on 4~6" of compacted gravel. I hate it. Constant weeds and even moles coming up in it.
Some day I'll cement it over.

We park our 14600lb fifth wheel on a 4" gravel pad. Leveled the site, layed the gravel and compacted with our dually. 5 years and still solid. Total cost $250 for gravel.

I dug out two "strips" and framed out of 2x4's so that the concrete would be even with the surrounding ground. The strips that I made were about 18" wide and about 4-5 feet longer than the wheelbase of the fw. My original fw was 23' I think, but also worked on my 31'. If yours is 40', I would think you would have to make the strips deeper. I also bought square stepping stones that are about 12" square (you would have to figure out the width to fill in the area between strips). As for the landing gear, make squares a little larger than you think would be necessary, in case you don't back up perfectly. I rented a mixer and bought the extra strength concrete, added the steel and wasn't hard at all (that was a long time ago though).

Why not just gravel all around, properly compacted? Many campsites (and roads) are gravel, and they work just fine, even with much more traffic than you'll see.

I park my class C on plain old dirt next to my garage. (Technically the low side is on ramps on the dirt so as to make it approximately level.) This started out as somewhat scraggly lawn, but the grass underneath the RV doesn't get much light and isn't really thriving. So far, this has not been a problematic approach in the least; it helps that the area is appropriately graded and doesn't tend to get soft or muddy.

sure you could. me, I'd do it right and construct a proper covered pad with an electrical post. and if zoning permitted I'd have a water and sewer connection.