Whether you use the Treasury or not, Lent is indeed a good time to start a new devotional regimen and to enjoy the blessings God gives through a regular, daily time spent in God's Word and prayer. There are other resources you may choose to use, such as Portals of Prayer (most LCMS churches have copies available for free), the Lutheran Book of Prayer, Starck's Prayer Book, or even the orders of service and collects contained in Lutheran Service Book.
Another wonderful book to help you invigorate your prayer and devotional life is Grace upon Grace: Spirituality for Today by John Kleinig. You may wish to read this during Lent to give some guidance for your devotion, prayer, and meditation on God's Word.
And don't forget Pastor Matt Harrison's book A Little Book on Joy with it's devotional guide in the concluding section entitled "The Great Ninety Days of Joy after Joy" (the ninety days from Ash Wednesday through Pentecost).