We currently tow (Taxa Cricket, 1800 lb dry, 300 lb hitch weight loaded with propane removed) with the Model Y. We estimate 33% range while towing and that's a pretty safe estimate with some buffer. Drafting and going slower can meaningfully increase your range. We generally only go about 90 miles at a time (which is about how far the super chargers are spaced out where we live), but have gone 110+ (which requires charging to full so not ideal). Super charging generally means unhitching because most require you to back in, so plan for that.
We're planning to upgrade to the Model X and get a bigger camper (Taxa Mantis, 3100 lb dry, maybe 450 hitch weight loaded).
With a 4000 lb camper + 500 lb cargo, you're looking at 450 lb hitch weight minimum, likely higher. Be careful. The MX max is 500 lb hitch weight. You might want to check your actual hitch weight of your camper loaded using something like an etrailer tongue weight scale.
Another consideration is how high your camper sits. I don't know the actual height of the hitch receiver on a new MX but
someone on the forums measured their older MX at 13.5" (low suspension). For an 18" coupler height, minus a 2 inch ball, that's 16". The max rise for the model X (and Y) hitch is 0.75", putting the MX at 14.25" (assuming the receiver is actually 13.5"). This means a 1.75" drop (nose down). Not terrible, but there are implications of towing nose up or nose down, so read about that. If you opt to exceed the 0.75" rise instead, that's going to put more torque on the receiver and lower the max hitch weight. To see what I mean, check the max weight for a bike rack, it's 120 lb on the MX because the added height increases torque. A 17" coupler height on the trailer would likely be better (assuming these numbers are correct). Anything taller than 18" is probably questionable towing.
One last consideration is payload. I've been doing some research on that. You can take a look at
this post and
this post for more information
