Maui is great for the first time Hawaii traveler, and gives a good dose of the adventure - the gorgeous scenery along with the famed hospitality, and staying for a few days, as you are, will serve you well. Lahaina is a good location to explore the island, plus it is relatively economical compared to Kapalua and the pricey Wailea. It also has a ton of economical eateries and night life along the main strip. We specifically stayed at the Hyatt - loved it, though it was a bit expensive.
Make sure you rent a car, as you will need one to explore the island.
Must-Do List -
- The Drive to Hana - culminating in a trek through the bamboo forest leading to the waterfall. The journey is the destination!
- Eat at the Royal Hawaiian Luau - a bit touristy. Hawaiian food, in my opinion, is bland, but the show is interesting and gives you something to write home about.
- Sunrise at Haleakala - Seeing the sun ascend above the hills amidst the clouds is surreal. They have biking tours on the way down. Also carry blankets/jackets, as it does get really cold!
- Helicopter over Molokai Sea Cliffs - if you are of the daring type, try the doors-off tour
- Snorkel to Molokini - Plenty of operators, and most provide lunch on board the vessel.
- Beaches! Go over to the Big beach past Wailea, Kapalua (a bit windy), and all the red/black/white/brown sanded ones along the ride to Hana - absolutely stunning!
A tip to save money - Some of the tours can get really expensive. Since you are there for an extended time, consider signing up for some timeshare presentations (though they mostly market to couples). You will have to spare 2-3 hours hearing some salesman trying convince you to spend $25,000 (lol!) on something you'll probably not use - but, in turn, they will offer you SIGNIFICANT discounts (may be even free!) on the excursions. Our helicopter tour was regularly priced at $189, and we only paid $69.