That's exactly how many many motorhomes are wired up (namely, those that come with an automatic transfer switch rather than use the socket setup with the generator as you have). The logic is sound and the setup perfectly reasonable. The one difference is that most don't have the extra 30A receptacle wired anywhere.
Are you planning on having this receptacle wired just to the generator, in parallel with the transfer switch, or to the output of the transfer switch, or to a circuit from the electrical panel? I think any of the options would be workable and legal and safe, but I myself would probably prefer it be powered from the electrical panel so as to have at least the 30A RV main breaker protecting it.