Hmmm, indeed, we do not have enough time, and we should start as soon as we can. Je Rinpoche's Lam Rim Chen Mo is indeed a very good start, but if you feel that Lam Rim Chen Mo might be a little overwhelming, I do have a few more suggestions on Lam Rim texts:
1. Je Rinpoche's Middle Length Lam Rim. It is a more concise text, and headings have been added by Trijang Rinpoche. However, there is a slightly different approach in which Je Rinpoche adopts to writing this Middle Length Lam Rim (though i am not very capable of explaining how, sorry about that! :/) and is indeed an interesting read and contemplation. Some of the major Lam Rim Commentaries have been based on this Middle Length Lam Rim as well.
2. Pabongkha Rinpoche's Liberation in the Palm of Your Hand. Despite many controversies surrounding him, I still feel his commentary on the Swift Path is concise, yet it is complete and profound. This text is more experiential, and that it provides a lot of guidance to beginners. I myself always refer to this text (and of course, Lam Rim Chen Mo) for my practice.
3. Panchen Lama's Easy Path, and the commentary by Gyurmed Khensur Rinpoche Losang Jampa. I personally would view this text more like a summarised version of Pabongkha Rinpoche's Liberation, but it is handy and easy to read and refer to.
A good book if you do not have enough time to mull over the lam rim topics extensively.
When we are more familiarised with lam rim, then the study of the more complicated texts (such as the major indian treatises) becomes less daunting, because we have some background knowledge of what is happening.
Personally, i am not sure about ngondro in gelug, because (if i never remember wrongly), ngondro is not a separate issue from the HYT empowerments, i.e. It is not given separately. However, it is also dependent on case to case basis, so it would be good to get a qualified teacher for guidance. FPMT does have quite a collection of qualified teachers, but i recommend that if you are adventurous enough, travel to india and visit the three great seats (Ganden, Sera and Drepung). You will discover a lot.
Hope all will be well!
Homage to the Mother of Buddhas as well as of the groups of Hearers and Bodhisattvas
which through knowledge of all leads Hearers seeking pacification to thorough peace
And which through knowledge of paths causes those helping transmigrators to achieve the welfare of the world,
And through possession of which the Subduers set forth these varieties endowed with all aspects.
- Ornament of Clear Realisation