2013 Kodiak AC

This may be a bit late but I was experiencing a similar situation in my 276bhl 2013. I spent one afternoon and opened up all the the vent and traced the ducting from the supply. I notice that there was some random spaces that were being used with no vents. Also when I opened the access from the ceiling there seemed to be lots of cross flow from the return air and the cool supply. So any way I went through and blocked off any unnecessary ductwork and installed foam at the end just past the last vent. Also spent about an hour using duct board and ul listed Tinfoil tape and seal off the return air and supply. It does seem like a lot of work but it truly was not bad and I really got to know the workings of my trailer. Anyway by in blocking and sealing my a/c works great. 90* out and I'm 75* ish (depending on kids in and out) in about an hour. I also carry an small 6"to 8" vornado fan that I help move the air around.