Upcoming run

I just got home from my middle of the day run and decided to take a look at the course for the race I am going to do in 3 weeks.  Keep in mind, I am running 3 minutes and walking 3 minutes, repeating the cycle 5 times to make 30 minutes.  That is what level I am at currently.  Very close to couch potato.
So, I looked at the course and the first thing I notice is that the elevation change is 197 feet.  Yep, that means a lot of up and down hill.  Oh, my poor knees and calves.
I am thinking I might need to go practice the route a time or two before then.
I think, by the time the race gets here, I am supposed to be running 4 minutes, walking 1 minute for 6 cycles.  Wish me luck.  I just hope I finish the race before everyone else has gone home.