Travelling slowly to La Paz with small child and pregnant - suggestions for stops on the way

Dear BoliviaBella, Myself and my one year old son are considering travelling from Santa Cruz to La Paz to visit my husband who has just started a short job there. I'm a bit scared about going to high altitude, for both myself and my son. I've been advised that after 2500m, we should go no more than 500m in a day (and spent a couple of nights at each place).

I think we will go via Cochabamba. Do you know of any good places we could stop of at between Cochabamba and La Paz, every 500m? (i.e. if Cochabamba is 2,700m preferably something around 3200 between there and La Paz). Also, is there somewhere to stop for a night on the way between Santa Cruz and Cochabamba?

Any other travel suggestions gratefully received. I'm also worried about Dengue, Yellow fever and Malaria in Santa Cruz.

Thanks,
Sam