Oh Adelle I'm sorry to read that she is so poorly. I wish her every good fortune. I do read about piggies leading normal lives on the correct heart meds, so I have my fingers firmly crossed for your little one.
Please discuss diuretics if you already haven't. Your vet will probably mention them anyhow if not, but if not, it's worth bringing the subject up, as they may or may not be appropriate for your piggy, and can make a huge difference.
I thought I'd mention it now in the hope that it is helpful before you go and see the vet, rather than retrospectively after you come back, being as repeated journies are something you wish to avoid.
@Wiebke @helen105281 to see if they can give tips before you leave.
I also recommend putting some cucumber in with her, to avoid the stress of dehydration.
Please accept my apologies if you have already thought of/discussed these pointers x