Our family used to grow these and yes these suggestions are correct. Another tip is that if the stem is still on it, the stem should be dry and brown, (like a stick).
There is nothing more maddening than getting home from the store and looking forward to a nice sweet tasting watermelon or cantaloupe and opening to find it unripe and quite bland. For the cantaloupe I like to smell them, usually if they are nice and ripe you will smell that sweet smell coming from within the fruit.
