How to serve drinks

I'm planning a reception in the park. Renting a large shelter and moving out picnic tables to bring in rented tables and chairs with nice linens and having string lights done. Sweet, fun, not very formal.
The park's rules are pretty liberal. They allow candles, glass and alcohol, just not liquor (so beer and wine only). Which is leaving me at a loss as to how to serve drinks with a buffet.
We could hire a bartender and a small cocktail staff. We'd get a keg of something local, find a bartender who supplies glasses and not worry at all about what sort of container the soft drinks arrive in, since the bartender would be pouring things into glasses. Pro: this just sounds easy Con: this is absolutely the expensive option (I'm sure I could bring the price down a little by going plastic, which wouldn't be terrible at our venue.)
We could set drinks up to be self serve. We could have a variety of bottled beer and get all of our soft drinks in glass bottles (we can get them at cost). We'd set up some nice ice troughs to keep them cold and hire someone to keep it tidy and stocked. Pro: more selection and it goes with a more casual feel Con: I don't love the idea of people having to get up during dinner to get another drink
Professional bartender and self serve are both covered by the liability insurance that I'm looking at, so they are equal in that.
What do you think? Is there another idea I'm missing that would work better.