Hooray, you're family is coming to DL for a first visit!!!
First, I would recommend reading "HydroGuy's tips" sticky at the top of the page. Great info for WDW vets and first timers too.
For packages, I've found the "Stay 3 nights get the 4th night free" deal the best. It's usually announced in June or July, and it's normally good for stays from September through mid December. I've booked this package two years in a row, the first time through the
Disneyland website, and this year I booked it through Costco.com. I actually like to book through Costco because you get a few extra perks thrown in that you don't get when booking through the Disneyland website. For example I got a quote from both the Disneyland website and Costco.com for 5 nights at the Paradise Pier Hotel and 5 day park hoppers for my family. The quoted prices were exactly the same, but since I'm a Costco member booking through Costco.com, we also got a $25 Disney gift card (just 1) and a free character breakfast (for everyone in our party).
If you're not a Costco member, but have a friend that is, your friend can book the package for you using their membership number. And you won't be required to show a Costco membership card at check in, so don't worry about that.
Some also like to book packages through Getawaytoday.com. I've also booked through them and have found them to be very reputable. My only qualms with Getawaytoday is they send you "ticket vouchers" instead of actual tickets, and in the past we would have to stand in line at a ticket booth to exchange the vouchers for actual tickets to enter the parks, which was a bit time consuming and annoying. But maybe this isn't the way it is now.
Also,
AAA can offer some great packages, so if you're a AAA member, check on their package prices as well and any extra perks they may offer.
For onsite hotels, all three can deliver a great stay depending on what you're looking for. The GCH is the most upscale, has wonderful theming, and the best location of the three, but they also have the smallest rooms, and with two teenage sons, I don't think I would recommend it. You'll either get a room with a queen bed and bunk bed (the bunk bed would be a little small for teenage boys I think), or you'll get a room with 2 queens. None of the rooms have sofas except the rooms with one king bed or the suites
I would recommend the DLH for you. The rooms are bigger, and many have 2 queen beds and a sofa that makes into a bed, which would be great for two teenage boys that don't want to share a queen bed. Also, many rooms have a large sink/vanity area seperate from the bath/toilet area, so that makes getting ready a bit easier for everyone. Also, there's the wonderfully themed Neverland Pool that you all might enjoy, great landscaping and waterfalls, a quiet pool, and although there's an arcade at the hotel, right next door is the ESPN Zone, which your teenage boys might like to venture over to and get a little "away from our parents" time.
Of course the PPH would also be comfortable since they also have large rooms with 2 queens beds and a sofa that makes into fairly comfortable single bed. The bathrooms are large, but the vanity/sink area is located in the actual bathroom with the toilet/tub, so keep that in mind for getting ready in the mornings. Also, the PPH has the longest waterslide (but least themed pool area, although it's still nice), and the pool deck offers nice views of the fireworks with piped in music/narration.

It's about a 5 minute walk to the ESPN zone or the DTD Monorail station.
Hope that gets you started a bit in the planning process. I'll be around (and so will many others) to answer any questions you may have.
