Can an avitar and inventory be parked without losing them?

Can an avitar and inventory be parked without losing the account, avitar, and inventory? I'm relocating for the next few months to an area with few options for a high speed internet connection. Durring this time logging in with the SL viewer is not realistic.

If the account has to be logged in with the SL viewer to keep the avitar, inventory, and account from being lost, how often does this have to be done, how long does the login have to be, and is there anything else needed?

Is there an alternative to logging in without the SL viewer that would prevent losing the account, avitar, and inventory?

Also is there a way to backup the inventory and/or avitar offline as an extra precaution.

If it's a basic account it will be saved forever.

If it's a premium account it is saved as long as you keep paying your subscription.

There is no need to log in to keep the account active.

They don't delete your inventory just because you haven't paid. You would lose your land though.