If you are worried about pick pocketers go to www.pacsafe.com they have slash proof bags and purses as well as camera straps. Great for guys and gals. I used the citysafe 200 and its great.
I did my first Contiki in 2001 alone!It was the best thing I ever did and I had an absolute ball! I am about to go to America with people I met on my last Contiki tour in mid 2006! Just do it!