You did not specify the direction of your travel, but I'll assume that you're doing the logical thing and riding downstream with the river. If that is the case, do note that your very first 30 km will involve climbing over 500m. That's a bit of a jumping in at the deep end, if there ever was one for cycle touring. I mean, there are people here who tackle 2k of elevation gain in a day without batting an eyelid, but most likely not on their first day touring - ever.
I suggest you strategize a bit about how you plan to tackle that. Soldier through and hope for the best? Make it a short day (shorter even than usual, given that it is advisable to make a first day of a tour short)? Skip the climb? Spend the remaining days before the trip in the gym growing huge calves and quads? Do a couple of prep trips, to familiarize yourself with a concept of climbing on a loaded bike? Everything goes, except just arriving there and finding out you're not ready for the beast.
Also, if you want additional advice, perhaps expand a bit on your tour. Daily distances? Kind of bike? Accommodations (hotels/warm showers/camping)? Season when you plan to embark?