Planning a vacation in March-April, around 10 days long for me and my girlfriend. So far I have Wyndham rewards with 2-3 free nights in a hotel. Now I'm deciding if I want to go to Hawaii or Las Vegas before I decide which rewards card to work on next. If I go to Hawaii I'd like to visit Volcanoes National Park, as well as learning about some great Hawaiian culture and seeing as much nature as possible, I haven't figured out if I want to go to any islands other than the big island yet, and if I do, then which ones I'd like to go to. If I go to Vegas, I'll pretty much let my girlfriend decide what we'll do as she's been there multiple times. After the Vegas stuff for 3 or 4 days we'd go to Utah and road trip/camp and explore a bunch of National Parks, 1 day each (Bryce, Glen, Arches, Zion, Capitol Reef, Canyonlands, bridges, etc.)
I think Vegas would be cheaper because I wouldn't have to pay for any hotels, in Hawaii I think I'd be able to cover around 6 hotel nights with credit card rewards and be on the hook for the rest, maybe I would stay less days if I went to Hawaii so it wouldn't cost as much.
What would the other costs be? I'd have to rent a car in Vegas to go to the National Parks, would I need to rent a car if I went to Hawaii? Should I just go to the big island in Hawaii, or visit another one? How much does it cost to travel between islands? What are some options for activities in Hawaii and how much do they cost? I'd like to learn a lot about the culture of 1-2 of the Islands while I'm there.
The credit cards I'm thinking about getting are
IHG Rewards Club Select after spending $1000 in 3 months get 60k IHG points, which is about 2-3 nights in hotels
Chase Marriott Rewards Premier Visa after spending $2000 in 3 months get 70k Marriott points + a free night at marriott hotels
Alaska Airlines Visa Signature after spending $1000 in 3 months get $100($25 basically because $25 nonwaived annual fee) also 25k miles signup bonus and $121 coach companion fare
Southwest Airlines Rapid Rewards after spending $2000 get 50k miles, $69 nonwaived annual fee
Barclaycard Arrival Plus after spending $3000 in 3 months get $400 for travel purchases (I might not be able to hit that spending limit)
United Mileage Plus Explorer after spending $1000 in 3 months get 30k miles, also $50 signup bonus
Are there better options from credit cards? Which ones should I go for?