Ha-ha-ha! It would actually be really fun; IF you are physically fit, young, and the weather is nice. And rather than using your arms, it would have to be some kind of seat suspended under the line that hooks to the line. A much more practical idea would be a train system that actually works, as @bongo mentioned.
Amtrak is a joke – if I wanted to take the train from Salt Lake City to my parents in Florida, it would take me to Los Angeles first, the trip would take a week and the fare would be $1,200.00. And as an added bonus, I couldn’t take the train home at all. It doesn’t go that way.
I would love to see an elevated monorail system, something like Disneyland’s. It would have to actually go to the places I want to go, and the price would have to be less than flying.