Two quick questions...
 

1. Can I use a paper Travelcard purchased at a National Rail Station for bus travel? Or only tube and train travel?

2. When taking the Eurostar to Paris, do I just take my own luggage on the train? Or is there some other system?

Thanks!

1. Can I use a paper Travelcard purchased at a National Rail Station for bus travel?
Yes. At least on TfL buses within the TfL area.

2. When taking the Eurostar to Paris, do I just take my own luggage on the train?
Yes
Or is there some other system? No.

Can't answer the first, but you carry your own luggage onto the train rather than checking it.

Sorry for my ignorance, but what is TfL?

Thanks again!

TFL + Transport for London (the name of the London transit system)

Thanks!!