NOPE, NO NIT PICKING, sounds like a reasonable cost effective method to me JD. A few thoughts:
Since its a 7500 instead of a 4000 and out of an RV my best "guess" is its indeed 120/240 volt which is great as the smaller RV gensets are only 120 volt. Smaller RV's use a 120 volt 30 amp (2 pole 3 wire grounding) plug, while the big boys with 2 roof AC's use a 240 volt 50 amp (3 pole 4 wire grounding) plug that has both Hots, Neutral and Ground. One AC works on one 120 VAC leg, other AC the other.
Sorry, I just dont know if it has its Neutral floating or not (i.e. it has a connection to the case frame), but since youre only using a two pole (2 pole backfeed breaker) transfer method, the gennys Neutral needs to be unattached from its case/frame and then when you get to the house panel it, of course, wires to the panels Neutral Buss. The Equipment GroundING Conductor (bare/green) runs out of the panel and wires to the gennys case/frame.
Be sure the enclosure is ventilated enough for that air cooled genset. Many of those RV gensets already have a fan on one end which vents to the outside so Im sure you can get that figured out
GO FOR IT I SAY