What software are you using?
I've Lightroom Classic CC on my main iMac at home. I also have a new MacBook Pro and an iPad Pro (512gb).
- If I use the iPad Pro, with Lightroom Mobile, I can import by raw files via the SD card reader, bring them into Lightroom Mobile and edit, and they sill sync back to the iMac at home. I have all 30,000 odd images synced between the iPad Pro and main Lightroom catalog, so I can work on any image (albeit a SmartPreview).
- If I use the MacBook Pro, I create a new catalog, import the files into there, and when I get home, I import the catalog into the main one on the iMac. I have a hard disk with copies of my original photo's I can use if I want to work on an older image.
Pro's of the iPad Pro approach for me are, it's very light, very fast, and practically zero extra steps are needed for catalogue management. You can pick it up and tinker any time and it's quick, and you can continue to do so when back at home too in front of telly! Oh and the Pen - that's excellent!
Pro's of the MacBook Pro approach are mainly due to the fact I have my full library with me in RAW format if I need it (which I usually don't when I'm off travelling, and the screen is slightly bigger.
Con's of the iPad Pro approach are, sometimes the import of the photos can be a pain - you have to import into the Photos app and then from the Photos app into Lightroom (this last step can be automatic). It can crash when you're importing (not for a while though - may have been fixed, but it will carry on from where you left off). Feature wise, there are some features in Lightroom not available on the Mobile edition, but noting I use now.
Con's of the MacBook Pro approach are the extra faffing with the catalog merge - means you have to do it once and you can't tinker with the images after without extra catalogue management.
I personally prefer to use the iPad Pro more than MacBook Pro,
Spec wise - while a larger internal SSD would be useful, external SSD drives might be more flexible, especially if you're sharing catalogues across to a 'home' PC.
EDIT - should add that Lightroom CC would remove the sync issues, but my bandwidth (20 down/5 up) means this just isn't practical; tried it but it just kills the broadband when I try to upload after a trip out and the kids are not happy!