Night, from where we are now, its EU reform and staying in, a very soft 'Brexit', OR a very hard Brexit.
A Hard Brexit can only be achieved if a50 survives the court challenge or if it fails that parliament views all other options on the table as inferior - and they are prepared to 'sell out' various groups or various provisions to protect these groups can be found. This may not even be possible. See Ireland. See Scotland. See EU citizens living here. See UK citizens living abroad. See all the various acquired rights. Or if the EU become totally impossible to deal with and this becomes the last resort option (but this in not in the interests of the EU for lots of reasons too).
A Soft Brexit may not be allowed by the rest of the EU. This may not even be possible. See the developments with Spain over Gibraltar for a very good example of why agreement could be difficult for starters.
The other alternative is a collapse of the EU and/or a political shift elsewhere in the EU resulting from various elections which sees the EU failing or having to make major unforeseen concessions we can't predict at this moment in time. A full scale collapse is unlikely but a political shift does look on the cards in many places. This is our route to a soft brexit, but would still have to overcome obstacles like Gibraltar mentioned above. Which is why an EU treaty for reform rather than a soft Brexit is more likely to come out of this scenario as it probably would exclude the need for bilateral agreements and would be a continuation of the status quo in many respects.
Staying in is simply what's left as an alternative. And there is an argument to say that although its politically incredibly difficult given the referendum result, its not actually completely impossible merely because its the status quo and the rest of the EU don't really want us to leave even now because its a threat to their own positions.
All options are still possible. None are really in our hands as a nation but are instead driven by outside forces/constitutional problems.
Just because the child wants a pony, it doesn't mean the child will get the pony for Christmas. Most parents would love to give the child a pony if that's what they really wanted, but sometimes that's just not possible with the best will in the world because they don't have the means to get the pony. The child can shout and scream all they want it, and it won't change the problem. The child might get riding lessons and that might not be good enough as that's still their own pony. Or somehow the parents might, work their asses off to get the pony, but the child then doesn't like the pony because it means they have to get up very early and work very hard to keep the pony and its not what they expected at all. Smart parents, however get the child to borrow a pony to demonstrate that owning the pony might not be so great afterall, and the child might then just shut the fuck up about wanting the pony much to the parent's relief. Of course this can backfire and the child decides after a week that the pony is great and that actually they do want the pony the parents can't afford, and this brings its own problems and doesn't expose how hard it is to look after the pony in the long run. The parents panic as this wasn't their plan and the child later regrets the decision when the reality kicks in that this is forever and you can't give the pony back.
Right now, we are borrowing the fucking pony.