As others have said, temporary field hospitals are a possibility. Hotels? Maybe. But large, open spaces would work better, I think -- football stadiums, for example. Easier to move medical equipment in, and things could be arranged just the way the doctors and nurses needed it.
But if the number of patients still overwhelms the system, I think the next step will have to be a heartless triage. Ration care away from those who are least likely to benefit and/or have the least to gain. All other things being equal, favor a seventy year old over an eighty year old; saving the eighty year old will likely only extend his life by a few years, whereas saving the seventy year old's could postpone her death by over a decade. All other things being equal, favor a patient with pre-existing diabetes over another who has pre-existing diabetes and heart disease.