Thanks for the info everyone. We will be doing a 2 month-ish trip from Quito to La Paz and will be stopping in Cusco (using Peru Hop for LIM-LPB portion). We did Machu Picchu back in 2015 and the salt mines from Cusco. We'd like to do Salkantay since we can do it independently and Rainbow Mountain as a day trip. The Peru Hop bus will drop us in Cusco and pick us up in Cusco however many days later we want, I'm thinking 6-7 days in Cusco for the trek and Rainbow. We've done a good amount of trekking and will have plenty of time to acclimatize, but will have Diamox just in case.