Peru advice and dealing with altitude

[glitterbiscuits]

My DH wants to go to Peru for his 50th next year.
Top tips needed please.
I like the idea but the one time I went to Tenerife we took a cable car up mount Teide ( the volcano) and I felt awful. Giddy and nauseous.

I don't want to get all the way to Peru and not see Machu Pichu.
I'd also like to try to see some condors.

Has anyone got any experience and advice to share please before I go off and research with travel agents.
I'm tempted to try to find an escorted tour.

That train was cancelled when we were there! I’m wondering how often it actually runs!

I’m due to go to the Atacama Desert and the geysers in 3 weeks! 14,000 ft! Cold too! I’m all prepared so hoping for the best!