It's time to discover this Offline mode for Power Apps model-driven app tutorial, that could be very useful is you've planned to work on such a use case.
What about having an efficient communication between users, you could use Dynamics 365 InApp Notification to interact with user without disturbing them and keep a nice overviews of your tasks.
Let's discover together this new feature announced at Microsoft Build: Power Apps Express Design Overview
Here is an article that answers the simple question: PowerApps Portal: Tutorial How to create a portal? Come and discover the tips around this subject!
Top 6 Benefits of Dynamics 365 Portal: Here an overview of Portal benefits that could ease your move on this wonderful technology !
Here a very nice article that will give you a workaround to have global CSS in PowerApps. Missing feature for the moment, let's see how to bypass it !
Microsoft Power Fx is the name given to the language used in Formulas in Canvas Apps. Microsoft is investing in this language to make it not only available in the formulas of Canvas Apps, but in several other places too. Today, we take a Microsoft Power Fx Overview on this new features ! And they look very promising !
Dataverse Solution Checker is a great tool provided by Microsoft on PowerApps portal that allow to check the coding and structure best practices of Dataverse Solutions.