I will be travelling to London for a week in late February and staying with a friend. Since I am on a budget and that I am very lucky to have free accommodation in London, I am planning on spending most days in London and doing only two or three day trips. I have read a lot on potential day trips from London but I am slightly overwhelmed so I would really welcome personalised suggestions. A little bit more about me: I am in my twenties, I have no interest in guided tours, I am on a student budget (so somewhere where some of the sights are free or cheap, I can spend no more than 20 pounds in sightseeing per day), I prefer small towns and villages to large cities, I like Roman and pre roman sites, I enjoy the work of British authors but am not a die hard fan of any. So far I thought maybe Bath, Salisbury/Stonehenge and maybe Rye?
Finally, everything I have read about public transportation in London assumes tourists stay in Zones 1 and 2. My friend lives in zone 3 but I'll travel to zones 1 and 2 daily for 8 days. What would be the cheapest option for me?
Thank you very much for your precious insight.