I had our warehouse measure the Curt Trailer Hitch Receiver - Custom Fit - Class III - 2" # 13028 you were looking at and from the crosstube to the end of the receiver measures 8" as you can see in the included diagram. view full answer...
Just the air bag of the Air Lift kit part # AL88203 measures 7 inches by 7 inches. It's wider than the brackets it mounts on so the bracket width wouldn't affect compatibility of your application. view full answer...
The Buyers Products Trailer Wiring Junction Box # 3375601101 referenced in your question measures 6.5 inches long, 3.21 inches wide, and 2.5 inches tall when the cover is installed. The mounting holes at each end are spaced apart 7.38 inches on center.
I have attached an image to assist. view full answer...
Yes, I can confirm that the Air Lift LoadLifter 5000 Ultimate Air Helper Springs item # AL88219 will work with your 1994 P30 Class A Motorhome so long as it weighs 14,500 lbs or more. Pretty sure your class A weighs more than 14,500 lbs but if yours weighs less then 14,500 lbs you will need the Air Lift item # AL88203.
They each have a 5,000 lbs load leveling capacity and come with all hardware and mounting brackets necessary to complete the install.
I recommend adding the Air Lift WirelessONE... view full answer...
The Greystone Built-in Microwave # 324-000106 measures 19" wide so it will fit that part of your cutout, but you also need to make sure that it can accommodate the 14" depth and 13-1/4" height of this microwave as well.
The included trim kit measures 23-3/8" wide x 15" tall x 13-1/2" deep with the mounting holes being 22-1/4" left to right and 12-1/4" top to bottom.
I have attached a review video and some photos with dimensions that you can check out. I'm not sure if this will last an... view full answer...