At this point May's hand is limited to one card - a hard Brexit with some small trade deal to protect vital industries (I'd assume the financial passport and car manufacture).
The price she'll likely pay for this is going to be high, both internally and externally.
Talking at the Q&A yesterday, Farron commented that it's pretty obvious that if/when we finally leave the EU, the Lib Dems will be 100% for rejoining as a full member and will campaign as such. As he also posited, more people, and more young people, voted for Remain than any party has ever won in a GE.
So the major issue for May is not just A50 now. It is to engineer something not terrible that prevents a united wave of pro-EU sentiment from washing her and the Brexit project away - in 2020, 2025, 2030...