Rookie looking for basic advice

The short story is that I have been doing pulled pork in an amateur capacity for a couple years - retirement parties, graduation parties, birthdays. I have done 2 for profit jobs but most have been for charity or at cost for friends. I've been using a homemade smoker I converted from an old wood stove. Works fairly well but I can only do max 7 butts and feed at most 100 people.

So all of that was practice for a longer range plan to get into a concession trailer and do it commercially upon retirement. I retired last fall and have been shopping for trailers - with limited success. One thing I'm surprised to find is that most of the trailers I've shown some interest in are ALL ELECTRIC. I also own a travel trailer and am very familiar with propane appliances (refer, stove, hot water). I expected concession trailers to have similar technology - especially the stove and refer. (Stove would be for beans and perhaps tamales - my current smoker has a flat top that I put the beans on.)

So I guess my main questions: Is an all electric set-up pretty standard? How does one deal with this for catering private parties and even prep in my backyard (I do not have a 50 amp plug in wired and prolly don't have the capability in my current panel.)? I imagine most festival venues provide electric, but I'm not so sure about other venues like breweries and such. Is a propane refer uncommon in the concession business?

Thanks for responses. So far it sounds like propane refers are rare. So I assume folks have generator for set-ups that do not have electricity - such as a private catering job, or my backyard. True?

Well that is good to know. Changes my plan slightly. I’m just used to propane appliances from the RV world. And they are so efficient! I wonder why more are not in concession trailers? And yes I’ve already been working with Health Dept. so I know what I need there. BTW another surprise for me was there the requirement for municipal water. I was told it was all but impossible to get a permit for my well.