You're living in a fantasy world if you think he sees prison time. I mean, he'd still have his security detail, how's that work exactly? Should he be convicted, he'll wind up with probation if for no other reason than to keep the Proud Boys from rampaging.
It would be amusing to have him check in with a probation officer, but he'd get court supervised anyway just to avoid the fiasco of violent protesters at the location.
That's assuming you can somehow assemble a jury that doesn't have at least one Trumpian on the panel who will give him "total exoneration" in the form of a hung jury, that you can keep the courthouse from being overrun, that you can exhaust his appeals, and that the prosecutor even determines that Trump is guilty from the tax paperwork they just barely got and files charges.