There will be lots of advice...
But in the end you will have find what works for you and your goals of your trip.
(it's like paddle and boat discussions....
)
If your route is going to be on some big open lakes or longer distances I would suggest using a double blade.
I just got back from my annual Agawa trip and I paddled from the mouth of the river to the Agawa Bay campground with sustained 30k winds and gusts to 50k. There is no way I could have done that with a single blade and I would not have even attempted it. (my choice of boat was a big factor too. It was a solo large volume WW boat)
Into a med to strong headwind you will at least be able to make some headway.
Since it is your first take that into consideration, there are plenty of routes that can be found that you can do at a much more enjoyable pace and still not see people and have that "solo" experience.
I would also make sure you have a good number of paddling K's under your belt, whether solo or tandem. It will make your tripping distance that much easier, also it will make paddling in tougher conditions much more bearable.
This year I am well over 2000 K's and I have not enjoyed paddling this much in a long time, most of it has been local get in shape paddles. (Being retired has it's benefits! ) add that with a lot of hiking prep has made the trips I have done easier, even in some sketchy conditions and situations.
Whatever you choose, just pick a pace that is comfy for you and have some built in time incase the weather goes south.
Jeff