About 35 years ago I did something similar on an overnight backpack in Kauai. I skipped the sleeping bag, just counted on the tent and thermarest – it’s hot in Hawaii, right? – which would have been fine except that it rained really hard the whole trip, most everything got wet, and what I brought to sleep in was a 50/50 cotton/poly sweat suit, which wasn’t soaked but it was damp. It’s surprising how chilly it can get at 68 degrees when you’re damp and not moving. Not dangerously so, but certainly uncomfortable! I learned my lesson.