Training for a race isn't like cramming for a test. Waiting until the last minute means squeezing every bit of effort into the last remaining hours before the gun goes off, hoping that somehow it will make enough of a difference, in your lacking physical fitness, to prepare you for 24 hours, no sleep, 3 running legs of varying length and difficulty, and 200 miles split between 11 of your friends. Or...they were your friends until you decided to NOT train until the three days leading up to the race where you thought you could run two-a-days on the mountain and make up for the months you procrastinated. To show up to Ragnar on Friday morning tired and sore will not a return invitation guarantee. So what should you do between now and Friday? What will help your race? What will make it so that your friends/co-workers/11 other distant semi-related-never-met-before-relatives ask you back for their team next year? Well you could show up with extra head lamps,reflective vests, and giant Coscto bags of swedish fish. Or, you could do something better, easier, and less expensive. Rest.
In the 7-10 days leading up to a big race there isn't anything you can do to improve upon your physical performance that won't take away from your race. Within that time period the one thing that can hurt your performance would be to do too much. A workout that is too heavy, too intense, or too long would directly require more recovery and risk injury. The same with energy spent away from training. The taper is not the time to embark on huge home improvement projects or schedule a big business trip. However it is a great time to go for walks with the kids, out to dinner with the wife, and de-clutter your office space. As far as exercise goes, by the last week of your taper your workouts should be down to 25% duration and intensity. This is the week where rest and recovery rule.
Nutrition shouldn't change except that you aren't eating the caloric volume you were when you were training several hours a day. Keep your intake clean with most of your foods coming from veggies, and lean meats then fruits and grains sparingly. Lay low on the fiber a few days leading up to the race and continue to drink your 64 ounces of water. With Ragnar your running mileage is broken up and your van is supporting you with fuel along the way so carbing up the night before isn't vital.
As a GPP'er that has consistently trained 5x a week for several months, you are more than prepared for Ragnar. So if your running mileage hasn't been what other runners' has you needn't worry. Being physically fit isn't just about running in one direction, at one pace for miles and miles. The Ragnar race is a perfect example of how anything can happen...and probably will. GPP'ers are up for anything. You are physically ready for this challenge and will surprise yourself this weekend by what you are able to achieve....that is if you don't do too much cramming the next two days.