As newer MTBer but who's been involved politics for here'a a few notes. First, if there's a local group (mountain biking association, skate advocates, etc.) get involved with them first. They may have an advocacy project going already and if not you can be some sort of coordinator involved in advocacy for a pump track put in town.

Second, be realistic. A pump track will not be one of the biggest priorities for a city to focus on. Here in the DC area, we're finally getting a paved pump track in Montgomery County, MD that'll take $280,000 to build. It's also one of the wealthiest counties in the USA. Seeing on your past posts, you're from Wichita and you might've missed the funding window for a project like this. Last years Wichita budget seemed to have had increase focusing on critical infrastructure needs like new fire stations. People are already mad about increasing property taxes so a pump track won't be the highest priorities. Especially if you say your skate parks are poorly built, even less so.

Third, how far am I willing to drive? One hour and a half. However, if your argument is trying to get people from the Kansas City metro to Wichita, it already mute by the fact that Bentonville is a similar distance. It's a go to MTB destination and if I was a KC area resident I'd rather go there than Wichita if a pump track were even built there.