JMT entry and exit points for Boy Scout 50 miler

In July, my BSA Varsity scout team will be completing a 50 miler and they've selected the JMT. Tenativly, the plan is to enter at Happy Isles and exit at Devils Postpile via the Red's Meadow shuttle. Just looking for any insight or suggestions anyone intimately familiar with this section could offer. We plan on completing it in 5 days.