NOTE: As you won't have access to your banker yet, you'll need to bounce all your crafted pieces off a friend or guild mate so as soon as you start in the prison you'll open your mail and there's all your lvl 1 gear!
whether you're running out of bag space, bank space or want to run another 7 characters for an enormous amount of Hireling raw materials, you will find yourself having the option each time to run the prison or not if you choose. Here's the tip: definitely run the prison each time! Here's why... If you're running just for the extra bag space, you'll still want to max out your Hirelings eventually on each of those characters and as such will want to leave the prison with as much XP as possible. Craft a lvl 1 set of armor - with the training trait on each piece - as well as making sure to have at least one of each armor type, light, medium and heavy. Make your weapon of choice with the training trait - all the additional training XP % will lvl them faster while you're running around the prison gathering as many materials and armor, and provisioning materials as possible.
at this point the next thing to remember is slotting as many of your main active skil abilities each time you lvl up while in the prison - I make sure my characters never get out of the prison without hitting lvl 5. you now have a solid foundation for your main skills, lvl ups for all three types of armor and most importantly a ton of materials for provisioning - and deconstruction of all the dropped gear.
Hope this helps - have fun.