Can I get off the train at a stop and then get back on a later train?
 

Next week I will be traveling from Amsterdam to Paris via train and it stops in Lille, France. I would like to get off (my boyfriend has some things stored there he needs before we go to Paris). Does anyone know if this is allowed or will we need to buy a ticket to Lille, and from Lille a ticket to Paris?

You'll need to buy two separate tickets. You cannot buy a train trip from point A to point B and get off and take a different, later train. The number and schedule of the train are printed on the ticket.

That's what I figured, thanks for the help!

In general, a train ticket allows you to travel along a specified route, and you can break your journey wherever you like. However, the trains from Amsterdam to Paris are high-speed Thalys trains where reservations are compulsory, and the trains from Lille to Paris are also high speed trains (Thalys or TGV) with compulsory reservation. Therefore, when you book the journey, you need to specify which trains you want to catch; if you do that, you can get a ticket that allows you to stop in Lille.

There are no Amsterdam-Paris trains that go via Lille to my knowledge and a perusal of timetables supports this, thus the answer to your question is mute. If needing to go to Lille, skip the Thalys trains with the $12-20 surcharges and mandatory reservation charges and take a regular InterCity train from Amsterdam to Brussels, then connect from there by local trains to Lille, then take the French TGV from Lille to Paris (Reservations required on TGVs). Buy all tickets at once, including TGV reservations in Amsterdam. Thalys trains are the only trains that go direct between Amsterdan and Paris (except an overnight trains) and they are often full in cheaper fare categories, such as passholder fares. If Thalys are full, the Paris-Lille via TGV, Lille-Brussels and Brussels-Amsterdam route is an alternative but takes a few hours longer.

Thank you all for your replies. I think I will follow the KISS adage and keep it simple stupid. I will just buy a ticket from Amsterdam to Lille, and from Lille to Paris. Or make my boyfriend drag his stuff around Holland!