I don't know about the training plans but an hour per day is ok to help with cardio fitness but you will need to add some longer runs even once a week will help to get you used to long lengths of time in the saddle. The more the better! 440miles over how many days?

During multiple day cycles eating regularly and enough to keep to you going can be tricky especially if it's hot since you will fill up with fluids.

If you are using panniers on the trip train with them fitted and loaded to the weight you require since it wrecks the balance of the bike and your hill climbing ability. If you put them on the day of departure it can really sicken you, better to get the shock over with when you can rest or adjust the balance now!

I hope this is of use to you.