If you are going to be eating a significant amount of nuts, I would suggest macadamias. At 200 calories per ounce you will be hard pressed to find anything more calorie dense. They have a very favorable O3-O6 ratio, unlike most nuts, oh and they are delicious! Plus being in hawaii you can probably find them for a decent price.
This tastes incredible and I often have it twice a day:
take 60 grams of coconut cream (it's also called coconut butter, coconut puree, or manna?)
small handful of walnuts (or any nut)
2 squares of Lindt 90% cacao chocolate, broken into small pieces
If you live in a colder climate and the coconut is too hard to stir, nuke it for 5-7 seconds. Mix all together and eat. AMAZING!!!!
I do this now on my bulk and have it in the morning and sometimes again in the evening. Gives about 700 calories each serving?
Also try using canned coconut milk/cream in some whey protein shakes. 1 can is something like 700 calories, so having that can with 2 scoops of whey and some water, will give you about 1000 calories.
Those two things I listed above will give you 2400 calories alone.
I use these banana/cocoa muffins a lot as an easy portable snack/breakfast/energybar kinda thing. I only have the metric but will try to measure in cups next time i bake them. But in case you have a kitchen scale here you go:
200 g dates
200 g almonds
3 tbsp raw cocoa
75 g Coconut oil
2 ripe bananas
1 tsp. vanilla
2 tsp. cinnamon
1/4 tsp. salt
1 tsp baking powder
Mix everything in a food processor. Put in muffinforms, and bake at 350F for app 20 min.