I Need Advice

It depends on how often and how far you think you'll be traveling ...

It’s hard to know the answer without knowing whether your travel will be consistent or variable.

Companies have different rules about accountability - some do not require you to provide receipts on a stipend but you may have to with reimbursement.

I would do mileage reimbursement...
However if you did stipends or vehicle expense allowances; stipulate that it’s for both mileage, fuel, and standard vehicle maintenance upkeep
Management needs to set the $/mile rate.

I would say Mileage, even that can be fairly costly, i know many employees love it as they make money off it. How about providing them rental for a day, if it is not daily/frequent travel. Our company adopted to a 60 mile radius personal vehicle use. Policy.

It actually depends on how the stipend is handled. You might come out further ahead because you can deduct "unreimbursed work related expenses" on your taxes if the exceed 2% of your income.

Short answer would be stipend

Long As answer would be ill make my travel plan and then compare both options

Monthly, they get very particular with miles. The records need to be meticulous and even then they find a way to make it seem as if they shouldn't have to pay.

Stipends. We do it with phones. Easier to track.

Stripends?

Fuel card