Loren,
Either plan will be a good fit for you. Keeping up your strength training sounds appropriate for you.
If you have a solid strength training routine you do not want to change, go for the TIME CRUNCHED Category 1 Cross Country MTB Build, Peak and Race Plan and include your strength work. Look forward in the plan and back off the strength work the day before a high intensity session. It is ok to put your strength work in the same day as a high intensity session on the bike but do the ride first, recover, then strength later in the day.
If you are ready for a change up in your strength routine select the Masters 40+ MTB Cross Country Build Peak and Race Training Plan. This plan has a strength routine built into it with specific set, rep and exercise guidelines designed to work in concert with the on-the-bike training.
Lynda