I'm not sure why you're having problems with Route Loop, it's always worked fine for me. Maybe try protecting the traces? But there are a couple of things you can try with your poured plane. If you have high speed rules, you can set up a conditional rule for spacing. Or you can do it manually with a pour keepout.
Go to Tools --> Options --> Routing --> General
Enable the checkbox for "Allow loops when rerouting"
Select a pin to route from (in Select mode) then type Ctrl+J to allow loop routing.