Reduce file size by using lossless mlv's, you get 2x more for the same performance in post. But it is not possible on all ML capable cameras.
A: Buy more CF cards if shooting for one day only.
B: As Walter said buy new battery/charging device or laptop with internal SSD with enough space for a day of filming.
If shooting for many days, then it gets interesting. I'm experimenting with that workflow lately. You should ideally have enough CF's for a day, than if it's ongoing filming, at the end of the day you transfer via checksum, Resolve has it. SSD's are not the best archival storage, so you should use at least 2 copies of your footage on separate fast and reliable HDD drives, in protective hardboxes, ideally in separate vehicles, and so on...
But I suppose you just need what Walter said; upgrade your laptop and it should be the cheapest and fastest option.