Hi Ken
One solution might be to take your debit card and make withdrawals from cashpoints as you go. This will give you local currency and you won't wildly misjudge how much money you need. All of the countries on your tour will have plenty of cashpoints.
As for the excursions, you can't book before you go but you can pay for quite a few of them with your credit card. For the rest, you could take extra money from the cashpoints. Closer to departure, we will send you a list of all the optional excursions, so you'll have a good idea of which ones you want to do before you depart.
Have a great trip - it sounds amazing!
Kind regards
Olly, your editor