I really want to buy this game but I'm trying to sell my desktop in favor of a laptop as I now work out in the countryside where i will rarely have access to the internet and was wondering which storefront will allow for the least complications playing this game?

Definitely buy here on GOG!
- GOG Galaxy client is optional
- no need to be logged in to install or play
- DRM free - you buy the game here and it's yours forever
- patches are smaller and come faster in form of separate installers
- you can download and backup all your installers without the hassle
- you can rollback to the previous version of the game in case of broken hotfix
- GOG has the best community and support

Edit:
- 30 days Money Back Guarantee (vs 2 hours on Steam)

While I agree fully. the ONLY reason I can think of to buy on steam is a no questions asked refund within 2 hours or 2 weeks (I forget but its close to this)

If your reason for buying lies in a refund policy I have to ask why you're buying at all.

For the same reason why I am glad my State has a lemon law. If I purchase a vehicle and within seven days it does not work properly I can return it no hassle. There are places which do not have that law. Knowing that there are options in case a product does not work as it should is protecting the consumers money.

GOG IS THE BEST!!!!!!!!!!!! ;)

In this case, GOG grants you a much greater privilege. The refund can be made up to 30 days after the purchase. No matter how many hours you spent trying to run the (broken) game.

To Illona's excellent list I would like to add GOG support. If you have a problem with a game, you can open a ticket and get the full (electronic) attention of an expert in getting it to run properly. They will work with you till it's solved (or will explain why it won't work on your PC).

A lot of people act like you are doing them harm when you suggest they open a ticket. But I've had nothing but good experiences with GOG support.

Please take a look here:
https://www.gog.com/forum/pathfinder_kingmaker/cannot_play_since_103

Keep in mind that game saves from new versions (depending on the particular game) sometimes are not backward compatible. So rollback is mainly for users who after patching the game cannot run the game at all.

Just to be clear, you're saying that I may have to go back to saves from before the updates in order to play? That's okay from my perspective at this point, but just wanted to know what to expect.

Thanks for the help btw!!

Not necessarily, but with Pathfinder and Owlcat - who knows - anything can happen.

Usually, developers should track their changes and mark the saves with game version stamps - whether the saves are backward / forward compatible or not.
Whenever particular update causes the game to be not compatible with older/newer saves (some big updates do), the game engine should reject incompatible save file and inform the user to update the game to the required version.
All big games do that.

Depends on if you can wait. GOG gets patches usually later as Steam.

For example, the 1.04 (2) patch that fixes the Windows bugs is since 2 days on Steam.

That happends with most of the games, so if you can wait on patches, i would prefere GOG.

If you are a Linux player, GOG version still misses Linux bonus DLCs, so you may want to go with Steam.

100% true.
I am a fckdrm evangelist, but I can say. If you playing under linux, buy Pathfinder:Kingmaker on steam!
GOG not only misses bonuses for linux, but also sometimes you have to redownload 30G, because there are not every patch is present to downloaded separately. Duh.
Usually I can say "buy from GOG, even if it's more expensive". Not in this case.