If you have the ability to use your entire body without any kind of limitations and if you have the kind of mental health that tends to be perfect in every single way, shape or form then you should consider yourself to be extremely lucky. A big part of the reason what that is the case has to do with the fact that there are people out there that suffer from some pretty terrible disabilities, and they need to be taken care of and included lest they end up marginalized and unable to experience life in the same way as others due to factors that they did not choose and are certainly not within their ability to control either.
Keeping the disabled in mind while organizing a party is really important. People with disabilities need to be able to feel like they are just like everyone else, and modifying your San Juan party bus so that people with disabilities would be able to ride on it is really not going to end up being all that big of a deal if you think about it. All you really need to do is add some kind of a wheelchair ramp as well as set some space aside that people on wheelchairs can use to end up moving around as easily as they need to.
When you do stuff like this you are basically acting as a really good Samaritan who keeps the needs of those that no one else thinks of in mind. Chances are that your party would end up becoming a lot more enjoyable as well since everyone would feel good about themselves and would want to take part in more occasions like this.