Your letter is ok.  I think you may be able to amend it slightly and maybe she wouldn’t  be  offended at all.  I would make sure she knows that you trust her and you just want to make it easy for her.  My suggestions -

Medicine dosage and time - yes, medicine dosage shoule be exact.  Do the times have to be so precise?  I always found that if we got a little bit off schedule it was not critical.  Maybe list the times and ask that she try to give the meds as close as possible to those times.

Bed and nap time - I would leave out the word "sharp".  Again, if those were approximate times it would be less offensive.  Maybe something like, "she usually naps at 2:00 pm and bedtime is normally about 9:00 pm."

I would also suggest that you make sure she has a number where your husband can be reached in an emergency or if she has any questions.  I am assuming that he is as knowledgeable about this as you. (I  know for a fact that my husband is not, but that’s ok because he knows where to go for the info.  If your husband is like mine, give him a list as well.)

One last thing, do you have any written authorization to give your mother-in-law in the event of an emergency so that she can authorize care at the hospital if it were required?  I used to have something here that I was given at the hospital 26 yrs ago when my son was born.  It is pretty generic and you just fill it in.  On it you specify your child’s name, date of birth, etc., who you are giving the authority to in the event you cannot be reached, and specify a time period (from a certain date until another date).  I don’t have a scanner here, but I will try to find my form and type up one just like it to share.  I always have filled that out when either of my kids were with someone else and I would not be immediately available. 

These are just some suggestions.  I do commend you for being so thorough and making sure your child is taken care of completely in your absence.  When the time comes for you to go to the hospital for the birth of your new baby,  relax and know that you have done everything to be sure your daughter is in good hands.  Good luck.