Bear in mind that most published adventures really aren't optimized for Play by Post. You'll want to give it a readthrough, and just imagine every encounter will have to hold your attention for 2 weeks.
For combat encounters:
First of all, personal bugaboo, ALWAYS roll initiative for your PCs. Waiting for everyone to post to acknowledge a combat started is a silly waste of time. People can post getting ready, reacting to early actions, and fumbling with their bows on their own gosh danged time.
You want to either tune down (or eliminate) the combats that don't matter, or change the context to keep the players engaged. For instance, a bunch of goblins hanging out at the entrance to a cave is supposed to communicate that there are goblins there, and then be resolved in like ten minutes at the tabletop. As a PbP GM, I'd recommend either tuning down the combat so it can be over in < 3 rounds, or making sure the goblins are doing something interesting, like trying to get to an alarm horn hung inconveniently far away, to keep the players doing something more than trying to slap their HP to 0.
For boss-type encounters, you want to avoid hard Crowd Control effects like Hold and Sleep, which basically tell a player they don't get to play. Bosses who rely on these tactics might require you to add a few mooks or change up their stats, or the battlefield. Try to incorporate environmental obstacles (Pushing, grabbing, and spells like Thunderwave and Telekinesis are great tools here), since the battle of attrition is less nail-biting over the course of weeks than the course of minutes, and you want to give not only yourself, but your players some cool fiction to write, and a good, interactive environment really helps keep players engaged in an action scene.
For non-combat encounters:
Don't hold back your adventure hooks and important information too hard. Not every post has to be an infodump, and not every character has to chatter their head off, but the last thing you want is the players to completely spin their wheels with no direction. A productive misdirection that will send them off into some hazard is way, way better than stonewalling and letting the PCs run off looking for the "golden button" that will move the plot. If the PCs can't find the evil villain's lair, lead them into an ambush that they can fight off with minions who have a note instructing them to take the PCs' ears back to some place near the villain's lair.
Be ready for the players to latch on to literally anyone that has a speaking line. If you need them to talk to the butler and have the butler give them a clue on their way to the master of the house, if you don't want them to interrogate the crap out of that butler, you have to almost literally kick them in the ass, or just skip the butler in a passthrough post, and communicate the clue some other way. Dialogue with minor characters can eat up a lot of time in a vibrant tabletop game, which inflates the fact an order of magnitude over PbP. Of course, some people see this as a feature, and not a bug. Read the "table," and make sure everyone's got something going on to interact with if you want to string along some side dialogue. Even if that's more side characters.
You need to balance agency with efficiency in exploration-focused adventures. How best to handle searching a room is fodder for a good fistfight between DMs. I can only advise you be generous with your players, and do your best to judge what hidden information would be most fun and productive for them to know, and to handle as many of those "hidden" rolls in the background as possible.
Other than that, published adventures can be pretty great for pbp, especially the more open-ended and less dungeon crawly ones. You just need to find the ones with the right traits, or the right ingredients, and make sure you take out all the time sinks that will drag a game down. Pacing is a good 75% of keeping a play-by-post game on the rails.
