MilesBuzz! - Best route/airline for DEN>FCO?

Trying to go to Rome/Florence July 20-July 29. I originally wanted to stop in Lisbon or Barcelona for a couple days, but couldn't find any thing to do that easily, and redemption seems pretty costly to make it a multi-stop. I can use UA, AMEX MR points, and KLM/Air France points, and don't have too many restrictions.
Whats the best way to do this? Thanks for your help!!

Trying to go to Rome/Florence July 20-July 29. I originally wanted to stop in Lisbon or Barcelona for a couple days, but couldn't find any thing to do that easily, and redemption seems pretty costly to make it a multi-stop. I can use UA, AMEX MR points, and KLM/Air France points, and don't have too many restrictions.
Whats the best way to do this? Thanks for your help!!
Which cabin do you want to fly in?

Which cabin do you want to fly in?

I'd like to fly business/first, but am having difficulty finding any availability.
Budget is around 85-100k miles.