Last June , my son wanted a "one-last-vacation-with-family" before reporting for R-Day.
We booked a one-way ticket for him to Newark with a stopover at the vacation location - Florida. We all had a great time, and saw him off at R-Day. We also were able to upgrade him to First Class (a surprise gift) using frequent flier miles.
Sometime during Beast he completed some forms indicating where he traveled from (PDX-EWR); no receipts, no explanation of the indirect route for travel to West Point.
He was reimbursed direct to his new cadet account, the standard rate for travel and lodging between PDX and EWR. While fair, it did not reimburse him for any of the unrelated travel expenses.
If he had used the WP offered travel, he would have received a one-way ticket to WP for the day before R-Day, gov't paid lodging for an overnight stay, meals, and transportation to WP on R-Day in time for in-processing. Some of his fellow new cadets from Oregon took the gov't transportation option.
For appointees, your candidate portal will have info on the WP provided travel option.
In other words, if you want to travel with your parents or meander around before R-day, it can be done. You just need to be sure to make your own arrangements and be sure to show up on time.