It should be discussed if someone needs to stray from the timeline, generally.
In the event of boring travels, there are a lot of "filler" tactics that can be implied. Seeing an animal, a flashback, dreams, a random odd short even (meeting old people on the road and fixing their wagon? Asking about their adventures?) Should one not want to imply these tactics, then I suppose they can 'fast foward' and wait for everybody to catch up with them. There's no permanent guideline for this, as a situation is fully dynamic.
Now I'm sure you're thinking, "well I don't want to wait eight posts while Mr.McInteresting does 10,000 things in a single day. The only thing that should be kept too, as a guideline, to be contradictory, is staying within my time frame. Example, if I post and it's morning, don't not exceed past morning. If I skip all afternoon and evening and post immediately into the night, then I can wait for somebody to catch up to the current 'time', even if they need to double post, etc, but should not post past the "night". This generally makes it easy to follow whats happening, and if for some reason somebody jumps ahead of my character time wise, then they may have to wait until I pass them once more.
Also, as a note, I will warn everybody (I'll try to make it '2' posts before warning) When I'm planning to jump a period of time, giving you a chance to tie up all loose ends. By no means is this going to be a forever day-by-day posting session. In ocassion, to rule out multiple back-to-back group filler posts, we will advance time. No sense in waiting four weeks for an army (28 posts, each, and if everybody posts once a week that's a full month irl to forward your plot progression.) This is also extended to anybody else, all that needs to be done is talk to me about a time skip, and I'll see how everybody feels about it. If it's important for me to hold off on these skips, meaning someone needs a little more time to tie up the "loose ends" of their current event, then that can be arranged and a time skip post poned.
Basically talk to me about your needs, and I'll tell you my wants. Just don't pass my character in timeline and we should all stay on the same course just fine. (Time Travel, Dimensional Rifts, and Other time-related anomalies are typically excluded.)
To find something boring is a personal opinion, but if the majority of you feel someone is holding the rest of us back from the delicious meatier posts, then we can all be civil and polite about asking whomever is in question to tie up their loose ends.