There's not a lot different, just takes longer. Assuming you weren't on the verge of collapse on the other long rides, there's not a lot of reason to do anything different.
On a 200k, you can easily hit headwinds the first 100k. On a 300k, you can easily hit headwinds the first 100 miles. Mentally, that can be a little taxing, but still, nothing to do but chug along until you hit the turnaround.
__________________
"be careful this rando stuff is addictive and dan's the 'pusher'."