IMHO, the ONLY things an ex-President ought to get are:
1. Normal pension. At nearly $200k today, that's more than sufficient to keep him out of poverty.
2. Secret Service protection - yes, every POTUS makes nasty enemies, making them lifelong targets.
3. Early access to Medicare if he's under 65 when he leaves office; otherwise extend normal veteran's benefits since he served as Commander-in-Chief.
Office and staff? Nada. As a FORMER fed.gov employee, he needs no taxpayer-funded office, staff, or travel.