Rats!

I'll be getting a rat eventually.

I'd like to get advice on training my new rat to be a good "to go" rat, i.e. go in a pouch with me when I go out, and spend a lot of time outside the cage being social (without crawling away somewhere I can't get it out of!)

I'm 45, but have not had many pets. Currently have one cat, and am not planning to get the rat until after my precious cat has lived her life to the fullest as my favorite snugglie. Then I'll want a smaller, more portable snugglie. I want to be prepared, so I'm starting to learn now.