We've had no problem getting loans or anything. Just purchased a new car with some financing. Nothing changed. You just need an address and good credit. Our address is the address at RVMail.com with our personal box number. Over three years and zero issues with banks, investments, loans, insurance, etc...
We didn't have any problems with any credit cards or truck loans using our Escapees mailbox address, only the RV. Some banks may not ask if you are full-time or not, but it was our experience when buying our second RV at La Mesa in Arizona that they said only one bank they dealt with would loan to a full-timer (Alliant). When we purchased our current rig, I just went through Alliant again since we've had a good relationship with them.