PRimer would be way below her. We got alpha for my DS cuz we US'd until we started K and I thought the Lego-like aspect and mastery approach would be better for him. Once we started adding MUS and SOTW - it kinda took off and he has been asking for more. Not so much more structure, but more to learn about. He is hungry to learn, but still very USly in the manner in which we use the curricula and our approach. Little sit down time - most of it being with math.
MUS alpha is nice. The blocks are awesome. He LOVES them. Enjoying building and playing with them - but not the C rods so much cuz the rod don't have the tactile bumps to count or to allow him to "build" with them. The program is great. We got thru the first few chapters (place value and number/block recognition) and were doing really well with it (doing one side of a worksheet every other day - along with LOTS of free block playtime). Then DH decided to "help" with school - DS had been asking for homework to do while Daddy did his....I left a MUS worksheet and a few other things like Discovery Movies, practicing letters on his letter boards, etc. Usually they picked movies. One night DH decided he was going to MAKE DS do the math worksheet.
Refused to allow him a movie or educational games or even just normal play time until he completed the worksheet....apparently DS was in tears and fighting with him to no avail....
Needless to say it turned DS off to math in a HUGE way. And ruined our relationship with MUS. He refused to come to the table if it was out, ran and hide and cried instead. So I have the complete Alpha set just sitting on my shelf collecting dust now.
Other programs we have tried since losing the MUS love - Miquon, Singapore, and Math Mammoth. WOW, these are great!!! So different from MUS, but in a really good way. DS is back to liking and enjoying math again. They are fun to learn with and fun to teach. Not what I expected, especially since neither DS or I have ever come across a workbook we liked....
Look into Miquon Orange and Red book. Get the Lab Annotations book. It is all "play" and discovery based learning. It looks weird at first, but once you get started it is really cool. We use it to intro the lesson - discover all about it, then go to the Singapore text and workbook. The teachers book for Singapore also is worth it - lots of great ideas on games, activities, etc to promote mastery of the concept and skill. Great if you are not mathy, like me. Math Mammoth is super cheap but great too. That is how we got DS back into math. He LOVES MM. I have found the three can easily stand alone. But since we have all 3 now, I am using them all and it is working. Miquon to "discover", Singapore to "learn" thru textbook, workbook, games, etc, and then occasionally use Math Mammoth for the extra practice (which he sure does need alot of!!).
Before you go with MUS (which is honestly a quite boring in comparison - very slow moving and repetitive). I would check out these. I brushed them off over MUS, cuz i knew the blocks would be a really good fit for DS and cuz he ws so resistive to workbooks in general, and it all just seemed so traditional schooly....but they really can be made to be fun and USly if you choose to bring in manipulatives and do the games/activities. THey use manipulatives, but also use concrete pictures. Encourage mental math. Are much more fun. I LOVE Miquon and how he gets to discover so much on his own. I like the way Singapore teaches the concepts of math - number bonds/stories BEFORE officially adding. Thru pictures too - Come up with number stories that go with the picture. Or Miquon making "number trains" which is just number bonds using C rods (we do it with MUS blocks even though they are not exactly the right scale). He is suddenly starting to "get it" and remember some math facts - not from drill, just from play and learning the bonds.