Several towing reviews of Rivian out there. 50% loss of range towing is going to be the rule of thumb for any EV, probably same with ICE. I'll just make it to coast with 10% reserve, 93 miles and #5k boat tow.
Always get the max battery you can afford, towing or not.
Can afford, and want to pay are two very different things.
I know there have been some towing reviews, but more information is better. OSM also seems to focus on numbers which, to my analytical brain is more beneficial than ability to tow over the Rockies. 50% loss is what I would expect and I am factoring for more than that (2.33 to 1-1.1 mi/kWh, which I think could be more accurate for Conserve to Towing modes). I know it is similar to the reduction you see on an ICE vehicle, and a coast to coast trip is possible, but I am trying to figure out my uses, where it would be a couple 100 mile round trip with not so many charging opportunities. Most of them are acceptable, but in one extreme case would add about 2 hours on a 6 hour tow when you look at the large pack to the max pack (where the large was already adding a couple hours compared to an ICE truck, basically doubling the trip time for the large pack R1T vs an ICE truck). That is a bit much, but it is also a trip I haven't taken before, but have been wanting to do. Maybe I borrow a buddy's truck for that trip if I take it, or put my car in someone else's trailer if they have room.
So I am weighing these edge use cases, vs the my typical use case. Originally this had me leaning toward Max Pack, but given more information and some deeper thought I am now leaning toward Large pack.