All you can do is just ask and see what they say. I have work with Oregon state parks for over 11 years and at first they said no then after the milo meeting back when it was only 9 holes they said hay we have other parks can you look at them. Thats how we got Dabney and rooster rock and they are in a federal protected area.
I have played at Oxbow park and even have a course map that was layed out about 15 years ago. Oxbow and blue lake are county parks and they did not want to put disc golf in or anything new because they are well used parks. During the summer they are way to busy to even think about a course.
Anything to do with Mult. county is a real pain and moves slower than any parks department that I have delt with over the last 25 years. the county is whats holding up putting in the MHCC course because they want a paved parking lot plus if you put a lot in then they want side walks to go next to the lot. Were talking a $100 thousand just to get parking going plus they have to many impact study,s that have to be done and payed for so I say go a head and ask but it would be more worth while to work with state or city parks than to ask the county.