I have to imagine it's a given you can suspend your your account for a while if you don't plan on playing for a month or two, then when you have more free time again, reactivate that same account and regain access to the characters you've spent countless hours building up. I imagine the PVP campaign you were associated with originally would be reset, but what about other character progress? Or guild membership? Is a levelling penalty likely to be implemented or is it more likely that it'll simply be as though you never left and you'll pick up your progress exactly where you left off.
I'm planning to sink many months / years into ESO, but I know my free time will get monopolized by other games / family / work from time to time, so I'm hoping the process for suspending and resuming your subscription will be made as seamless as possible.