Gifting investment Real Estate questions and comments + deductible carry-forward?

[Jan Boldt]

Domicile: WA State (income tax free)
Property location (Texas): (income tax free)
LT gains + Depreciation recapture ~ $300k on a $500k income property ~
effective / average tax rate = 12% for past umpteen yrs (relatively low income, avoiding IRMAA and doing Roth rolls (no 'realized' income, just transferring from tIRA to Roth = vast majority of annual MAGI income)

In the end (coming soon, ~17 yrs) ALL remaining estate will go to charities / Charitable Foundation / DAF. At the moment, have plenty of financial glide path, so don't need the equity of the current Investment prop, but had planned to owner finance (extra monthly income flow @7%, fluff... more income not required to eat, clothe, house. ).

1) Cursory look indicates 30% max AGI can be deducted if deferred to Charity. (I can just do more tIRA withdrawals to tweek AGI to suit)
2.) 5 yr carry forward of excess deductions - (could use to draw down ~$800k tIRA BEFORE RMD or more Roth rolls)

Situation: Very desirable but very hard to sell income property (older (1979) small, low value Mobile home,(home = ~1/6th the value of property - Banks don't lend with that ratio) Beautiful acreage, (3) large shops, pond, barns, Very livable cabin (knotty pine!) nice setting, 100% included in new FEMA 100yr flood plain. (never flooded (yet), ZERO chance of home flooding (raised elevation), Shop might get a wet floor. (lower elevation). But Flood insurance is required as primary ($2000 / yr)

By the time I fix and sell the home (8-12 months estimated) and incur additional costs + holding vacant, and selling expense (SQUATTER RISK, <100 miles to MEX border), and then go back and recapture depreciation + Capital Gains... my TAKE HOME will be far less than the appraised market value. ~50% haircut.

So... since all goes to charity in 15 - 20 yrs anyway... why not donate now and play those cards? (quick resolution and 5 yrs of max deductions. (which probably will bump me to 28% IRS rate)

Any experience, or guidance appreciated.
(How to deal with existing mortgage during the gifting process... prefer mortgage gets paid off, rather than become part of the gift.)
Much thanks