Hi @brody182
All that should really be required is that you enter your email address, etc in the settings page in Membership. The rest is controlled by PayPal.
If it’s working with something else on the same site but not with Membership the things to check are:
>> PayPal information on the gateway screen
>> Do you have pages set up in Membership > Options > Membership Pages? If not click ‘Create Page’ for each.
>> Do you have Permalinks set to ‘Post Name’?
>> Are the subscription plans and access levels all set up correctly?
If all of the above is correct, you should be good to go, I have this set up on my site and this all works fine(using sandbox).
As for guest checkout, why would you want that? The whole point of membership is to create memberships, recurring payments, if someone signs up as a guest, you won’t have their information, nothing is set up on PayPal and you won’t get the second payment. You need them to have a PayPal account surely.