Two months is about 60 days, well within the 90 days permissible under the VWP.
You need to have evidence that you can afford to stay in the USA that long without working, and it will help if you have a return ticket (not so much for having the ticket as for demonstrating that you have definite concrete plans for when to go back home).
In general, the more concretely you can describe your plans (where will you go, and when, who will you stay with, what are their contact details, what is their relation to you and why would they let you stay with them), the less risk do you run of trouble at the border.
What you need to avoid is giving the impression that you will be doing any practical favors for your hosts in exchange for getting a place to stay. Even occasional babysitting, mowing the lawn, or other chores around the house could be construed as "work" if you meet a border guard who had a bad day and needs someone to take it out on.
Don't be unduly alarmed, though. Most visitors don't have trouble, and your plans are not so much out of the ordinary that you should expect any.