Which trip is better to choose?

Both are excellent trips, in fact, the one you don't choose this time should be the trip you take next time. The 8 day trip looks like it would be pretty busy and a lot of traveling while the 5 day trip does include some travel, but everything is a little closer together. If your driving from destination to destination, I would definitely take into account the gas prices when making your decision. I would choose the 5 day trip for that reason.