Boondocking Prep

1650 sounds high for the panel to me.  I got a 120 watt fold up unit for about $160.  It easily folds up and can be stored when not in use.  If you are using it only for fan, lights, and TV it seemed to work pretty well for us.

When installing a solar system everything is a trade off.  First off you need to find out the wattage needs you anticipate then size the system for that.  The first trade off is if you permanently mount the panel to the roof of the trailer then when at your boondocking site you will want the solar panel in the sun shine which means the trailer has to be parked in the sun the majority of the day, just another outcome. 

I can't help you with the roof measurements because mine is an older model (179/2019).  Maybe you could talk your way into the storage facility with an 8' stepladder??  The size and type of battery bank will be another important link to your system, so look at that carefully.  The pricing looks pretty good for the system but there will be additional costs, but still it stands now @ about $.86 per watt which is pretty good.  Still it depends on the performance.  You will not be able to run any high draw appliances like the AC, Water heater (on electric), microwave, or fridge (on electric).  Make sure the manufactures stand behind their products even through e-trailer.  Also make sure there are no compatibility issues between the e-trailer system and the type of batteries that you have decided on for use in your battery bank.  This should get you started.

For what it’s worth I decided to experiment with solar this past summer w/o spending a bunch of money. I bought a 100 watt solar kit from Harbor Freight for around $170 it included every thing needed to charge my OEM battery on my 2020 RP180. I do not run an inverter so the AC and microwave are unusable but everything else works on 12 VDC. I never saw the battery charge below 75% and most mornings the battery was back to full by 10am, one rainy day it took until 1 pm to reach full charge. We boondocked for 3 weeks straight with out any problems. 

I also use a 100W Renogy kit (suitcase style) but they also make them for  permanent mount. For our purposes - keeping a single 12v deep cycle battery fully charged for lights, waterpump, fridge  motor,  furnace blower, etc - 100 watts is more than adequate. Here's a link to a 100 w Renogy rooftop kit, for just over $300. They have 200 W kits for not much more. Each 100W panel is roughly 42x20 inches - x2 if you go for 200 watts. I have a 179 so my rooftop measurements wouldn't be of help to you.