I moved this year to a cottage with self contained annexe. Our first priority was to totally refurbish the holiday let and I decided that putting it with a holiday rental company would be the best thing for us, and that has paid off with continous bookings from the date it was ready (27/6) until 10th October. Have a couple of other bookings this year, and one already for next year.
The rental company charges quite a high commission (23%), but have got more bookings than I could have done by myself. It also gave me a completion date for the works.....I think if we hadn't had that we could still be doing the refurb!!

As mentioned by kazschow, it is a big commitment every Saturday. It takes me approx 3 hours to clean from top to toe for the next guests. Also, when you work out your budget for 'kitting' out the place you will probably have to double it.
Luckily most of the people have been really nice - but it is surprising how some people leave the place! A website I've found useful is
www.laymyhat.com, might be worth taking a look.
With regard to the CL, I looked into that for here. We would have to spend quite a bit on getting water, grey waste drainage and chemical toilet drainage to the area we had earmarked for this. We found that without electric hookups we could only charge approx £4 -£5 a night so felt it would take too long to recoup the costs of setting it up.
Good luck with everything.