Define the space before the gear
Your tent footprint sets light wattage, extraction rate and pot size. Measure the physical space first, including door clearance and ceiling height, then work backwards to equipment.
Pick a medium you can recover from
Buffered coco and quality living soil both work. Soil forgives feeding mistakes and moves slower; coco moves fast and punishes irregular watering. Beginners usually recover faster from soil.
Lock a schedule you can actually keep
A grow fails on the days you are not there. Decide up front who waters when you travel, and automate light timing before day one.