Please advise camera rigging on a slope

[Jaan Kristjan Utno]

Thanks for taking the time to read this. 

I am going to be shooting in the LA Riverbed and am currently figuring out potential shots with my stunt co-ordinator. 

Our sequence involves a character pushing himself up the sloped side of the riverbed, making it to the top and tumbling down again. I want to pull off a shot tracking alongside our character as he slips, barrelrolls and meets his demise. On the stunt side we have our blocking figured out for the most part, but I am not sure how to pull off this shot with the utmost safety and capability of control. 

Ideally, the shot will have the camera alongside the actor tumbling down a 45* slope. My immediate thought was to use a speedrail setup with a dana-dolly and an angular base, but my biggest concern is how to lock rails in to position. With a lack of experience rigging, I wanted to see if anyone has thoughts! 

Alternative thoughts are also welcome, but my budget is that of a student film - small and practical. I can pull this shot off with a technocrane, no problem, but how to do it with a budget that can't get anywhere near that?