Beth,
I'm glad to hear back from you! I was thinking about you and your situation and was worried for your daughter.
Turning the Britax Marathon (besides being a great increase in safety), may help a lot, as it will slightly alter your daughter's center of gravity so that she's bearing the weight on the back of her buttocks rather than her thighs, and her lower legs and feet will be supported rather than dangling.
When you buckle her, encourage her to scootch her tush all the way back into the bight of the car seat so that she's not slouching.
I look forward to hearing if this helps!
I'm glad to hear back from you! I was thinking about you and your situation and was worried for your daughter.
Turning the Britax Marathon (besides being a great increase in safety), may help a lot, as it will slightly alter your daughter's center of gravity so that she's bearing the weight on the back of her buttocks rather than her thighs, and her lower legs and feet will be supported rather than dangling.
When you buckle her, encourage her to scootch her tush all the way back into the bight of the car seat so that she's not slouching.
I look forward to hearing if this helps!