Little Nav Map can be used to combine flight plans. Load the first and append the second. You’ll have a plan with a “layover” where the landing from the first and the takeoff from the second coincide. “Shift CTRL left click” that point to delete one of them and get a continuous plan. Append the third plan, delete one of the duplicate points. Append the fourth plan, delete one of the duplicate points… etc.
Tedious? Yes, if you don’t do it as you go. Prone to error? Absolutely, if you don’t learn the keyboard shortcuts or save after every few additions. You’ll end up with a plan that will give you exact times and distances. I’m glad that I thought to do it only 25 legs into it instead of the end of more than 1000.