a call I believe they have a referral system the same as a number of the manufactures who only sell direct from their factory. They will match you up with a current owner in your area - most of the manufactures will give them a little kick back of some sort for doing it- discount on next trailer or parts or something.
There is a thread here
where people state what mods they have done to their trailer since purchase - many of which are options that could have been put on the trailer to start with.
Although I have a 16' the options you have listed so far are also all my must have. I had to add the Fantastic Fan & outside outlet to mine and I recently purchased a front overhead bin, it already had the rear ones. 3 way fridge
is a must for me as well as I want to have lots of options for where I camp. LED lights
would be another need. If Scamp offers pre wiring for a solar panel
I would get that as well - another item I added.
For me the Fantastic Fan does the trick as I also need to keep the trailer weight
down. Would not want to live without the awning
though!! Love it both in the rain and in the sun for extra shade. It more often than not the one thing friends who dont have them claim to want - so they end up packing a pop up canopy instead which in many cases weighs more than the awning.