I've played and DMed for 3e, 3.5e, 4e, and Pathfinder.
I like Pathfinder and 4e both, but I'm not going to sugarcoat it for you. Going from 4e to Pathfinder can be rough, especially for a DM.
.......
Ultimately, going back to Pathfinder broke my group in half and we never recovered. Some guys never cared for 4e and didn't want to go back, and the ones that liked 4e refused to keeping playing Pathfinder over rules frustrations, such as a failed save basically ending game night early for them.
Ah ahh ha ha!
Wow! This is spot on!
My friend, a long time 4E player attempted to run the Pathfinder mod "We Be Goblins!" (an outstanding adventure by the way!)
First fight in, he has to flip open the Bestiary to find a giant spider, and listed under the spider is simply the word "web"
and he was like "what they heck does that do?" so we got out the iPhones and searched the pathfinder/prd and spent 10 minutes finding it, then he just said, "forget it! it bites you" (he used a different "F" word)
There's tons of keywords a DM is supposed to know like: rend, web, constrict, grab, etc.
http://paizo.com/prd/monsters/universalMonsterRules.html
My recommendation is try out D&D Next. Converting a Pathfinder adventure to Next on the fly is actually pretty easy to do.
If you are still dead-set on Pathfinder.
I recommend getting your players to create characters using PCGen it's free
http://pcgen.sourceforge.net/01_overview.php
Study those universalMonsterRules, and all the spells and feats your monsters will use.
I recommend some houserules:
Don't force someone to play a "Healer". Use Reserve Points from Unearthed Arcana
http://www.dnd-wiki.org/wiki/Publication:Unearthed_Arcana/Reserve_Points
or just hand out Wands of Cure Light Wounds, like everyone else does. (I hate that)
Let Ability Damage and Poison only last one combat, and/or just be very liberal with allowing Heal Checks or Endurance checks to remove Ability Damage.
Also, use "Hero Points" that allow players to reroll saves against debilitating effects. And vice versa, allows the DM to let certain story-important NPC's bosses make their very important saves vs Color Spray or Hold Person. It helps alleviate the absolute wonkiness that the dice can cause, which in previous editions was handled by DM fiat.
http://paizo.com/pathfinderRPG/prd/advanced/advancedNewRules.html#_hero-points
I'd use Hero Points just like the link above, but use the following method to dispense them: Give every player 1 hero point at the start of an adventure, and also give the DM 1 villain point for every player in the game. You only get new Hero Points on achieving certain plot points, set by the DM. Such as completing a plot-quest, defeating a certain sub-boss or boss, etc. Also give them out for spectacular role-playing or self-sacrificing action.
Only let 1 hero point ever affect one action. So if a player chooses a very important action to use his hero point on, the DM can't also use his villain point to affect that same outcome.
The Hero Points will help alleviate the corner cases of the Gelatinous Cube taking out a Fighter for 3d6 rounds who failed his high Fort save. Or the level 4 boss who is Color Sprayed into blindness and stunned.
I'd also let the Cure Spells all be cast as swift actions, and ranged 50ft, but that's me, and the D&D Next designers.