I am not an attorney.... nor do I play one.. but, here goes.
When 'parked', the RV is NOT in use. Yet, by the very nature an "RV" can be moved and should be used...
Simple logic. Yet, I would definitely have a 'documented' discussion with my 'provider' about the fact that I 'use' the RV for 'extended periods'... it may not always be 'moving/underway' and in fact could be static for 'a time'. If the 'provider' limits you, or says.. "are you living in the RV?" , your 'policy' may not allow that.
Remember, insurance is 'risk management'...and be prepared to have a clear discussion with your 'provider'.
With there being more folks who 'full time' in their RV's or have 'extended' times of use such as 'snow birds', some 'providers' may have limitations....
I spoke to my own provider and was told 'No limitation on amount of use on the RV.' I park it on my property so it is 'safer' than in a storage area... and my insurance went down for that reason because the 'storage' facility had no 'responsibility' for damage, theft, etc.
Your mileage will vary.... good luck with your 'provider'...