Well other people have dealt with the timescales and details of article 50.
Note however that the two years is supposed to be both preparing to leave and a renogotiation, however this has been refused by Cameron. The idea is that the EU would try to keep a country in by offering concessions and the country would then put it to it's people. By refusing a second referendum Cameron appears to have blocked this route. Foolishly in my opinion.
As to what would happen economically that is problematic. One would be forgiven for thinking that detailed forecasts and plans had been made by the civil service ( the only institution capable of such) but... These were blocked by Cameron.
Indeed he stridently refused to allow the civil service to even consider Brexit in case it favoured the leave campaign. Leave campaigners knew they could use freedom of information laws to access any documents relating to Brexit so our sitting Prime Minister refused to allow the civil service to even minute a single meeting to discuss it.
Shocked yet? Well think of the implications..
We are about to have a say in deciding government policy. We either commit to ever closer union with all that entails ( EU Army as mooted by President Junker, further countries joining, fiscal policy decided by the EU etc) or we decide to go our own way and set sail to trade with the rest of the world.
There is no middle road, no status quo. Our treaty obligations are clear with regard to ever closer Union. It is either accelerated EU integration or out, as the EU will clearly see an in vote as the matter put to rest for a couple of generations, by which time nothing could be done anyway.
Given an out vote the government has no plan, no clue and has actively prevented any from being made.
Hence when Cameron et al accuse the Leave campaign of not having a detailed economic strategy they are merely attempting to hide their own extreme negligence. It is a self evident truth that the government of the day should consider all possibilities and plan for them, no? Well they haven't and are being thoroughly dishonest in their scaremongering campaign.
The leave campaign can make their case but it can only go as far as expounding on their vision.
We are offering our Prime Minister more power and more responsibility, he is clearly telling us, and frankly showing us by his actions, that he is not up to the job.
Never in the field of British politics has so much been withheld from so many by so few.