I'd suggest figuring out how much solution you will need and then take just enough stock solution to make that up, with water, at the location. Small bottles can be found from a good pharmacist or a darkroom stockist (if you're lucky!).

Print dev is often 1+9 or 1+4 while fix would be similar. Stop bath is such a low concentration that it might be easier to mix the few drops needed with a little bit of water and then take that small amount, making the appropriate calculations to end up with the correct mix in the tray of course. All this pre-supposes that you will use the chemicals once only and then dispose of them at the site - if you have to bring them away with you then it's all different of course.