...
If you want the most bang for your buck get someone to donate the food, and just charge an entry fee.
It is my understanding that the Outback and sister companies are generous with the donations of food.
We have been on a few rides, usually escorted, to raise funds and/or awareness and the entry fee was something like $20 plus $5 for 50/50, which included a lunch at Outback. They are not normally open at lunch so the place was all ours. You have to pay for any beverage other than a soda. You are advised to tip accordingly to what the lunch would have cost if you had paid for it

and if you get a few hundred to turn out for the event, between the entrance fee and 50/50 drawings there is a lot of opportunity to raise quite a bit of money. A lot of advance planning is needed to advertise, get insurance if needed, arrange to have police assistance to cross busy roads. All depends on how many people you can get to show up in support of your cause.
We heard of a poker run type of ride held in Canada where there was no need to man stops. They put a big container - like a pretzel jar - on a tree or something like that, and put assorted children's building blocks into it. People are to draw a block, record themselves what picture is on the side they are choosing from the block. At the end of the ride, someone has a code of what the pictures on the blocks mean at each stop, and they can add up the points. Then someone only needs go back past the stops at a later time and pick up the jars. Low cost, no man power....
