Just starting RotRL with just two players and playing using an online tabletop to make it even more difficult, but have taken the following steps.
1. Higher average starting stats basically an array from 12, 13, 14 , 15, 16, 17 each
2. max hp at each level, helps with the survival rate of less bodies to attack
3. started them off at 2nd level but with two classes each
currently they chose Ranger/cleric and fighter/sorcerer
4. lack of rogue is a concern but both lower level cleric and sorcerer spells should help and maybe a few old school broken doors
I may introduce a fate point or similar rule to avoid any show stoppers as I would like to get them to enjoy the campaign and at least not end it after the first installment Burnt offerings
Also using a auto level system throughout adventures so that they maintain a level or so above required basically by inserting level up point in the adventures through out the campaign and work out the level of magic items at star of each book via the pre gens and distribut similar value through previous adventure book.
Hopefully they will enjoy and we can rinse and repeat process for next pathfinder campaign