My number one recommendation is to not worry about much later down the road, but just pick a curriculum that works for you and your child and stick with it for several years. Consistency usually pays off more than finding an elementary level curriculum that aligns with higher math.
I have used RightStart with all of my kids. My oldest is in Pre-Algebra this year and is doing fine. RightStart gave them a wonderful foundation for continuing math. They are all very active boys and we liked how there were fewer worksheets in Levels A and B then increased as the kids developed the coordination and attention span to do more work.
Oldest son– did Level B 1st grade, C in 2nd grade, D in 3rd grade, then switched to an online school for 4th grade where he immediately tested at a 5th grade math level thanks to RightStart. Now for 6th grade he is using Saxon Algebra 1/2 at home and is doing great.
Middle son– Level A preschool, B in 1st, C in 2nd, D in 3rd, then switched to a different school where he also tested very high in math in 4th grade
Youngest– Level A preschool, B in 1st, C in 2nd