As I was explaining in another post, the Spanish government mishandling of the crisis is totally unacceptable and the ineptitude of some of the ministers is astonishing, they keep wriggling every which way with no clear planning ahead. This is to say that at present, even to those of us living here, there's no clear line on "what's next".
While it's true that any plan will depend on the evolution of the crisis, a viable and comprehensive short term plan should be available... and it's not, not to the public not even among the member of the Spanish government -judging by their contradictions.
So any advice, by anyone, it's just pure guess and speculation.
Having said that, my gut feeling with the information I have (now), it's that if (if!) the curve has in fact been reached, life will return to something sort of "normal" (mind me!) by late June. Tourist places will be mostly up and running albeit it's likely there'll be certain measures in place that will alter regular visits (ie. social distancing, maximum capacities inside premises, etc).
Note however that several reports made by local consulting companies, like Deloitte or DNA, seem to point that for the time being tourism will be mostly internal, short trips within the regions for the most part.
This, of course "can" be an opportunity for those venturing to visit from abroad: far fewer crowds and possibly cheaper prices, but on the other hand, you're still likely to be exposed to supervening situations (cancellations without much pre-warning, forced quarantines if a new spike is detected, etc.).
Cancellation refunds and the like are something that the machinery of our tourism industry, quite developed already, is well greased on so, for the most part, there should not be any problems if you come up with the need to do so. Still, as in every industry, not everybody sticks to professional procedures and ethics, so make sure to understand who you are booking with AND do read the fine print -the devil is always in the details and most people don't bother to read it!
It's worth saying that this scenario won't be unique to Spain but to many other countries, especially those accustomed to receiving tourists.