My DS5 will technically be in K next year and we will be doing LLtL1 and RLtL2. I know that he could do LLtL1 now, but our focus is on finishing up Progressive Phonics first (which has worked wonderfully). We did half of AAS1 this year for PK4, but switched to RLtL1 (we started at lesson 14) and have been MUCH happier.
LLtL1, AAS, and McGuffey/Treadwell readers may be too much for 1st for many kids, but I think it really depends on how many days/weeks you school. We plan to only do LLtL1 twice per week. As I recall, there are 108 lessons, so I expect it will take us about a year and a half to finish, which is why we are beginning it over the summer. If you plan to do LLtL 3 days per week and AAS twice per week, along with the readers, it could be feasible. I just prefer to leave Fridays for other activities. You could also just switch to RLtL, which uses the Elson readers and teaches spelling, and be done with it.