As soon as you get this item. Before you make any "big decisions" on factions. I would recommend using it to relocate your base to a more satisfactory location. Sanctuary makes a horrible base of operations and this grenade allows you to load up with thousands of pounds of loot, and drop it off at your new home. Pick a base with 2 or less settlers, towards middle of map. Never build a recruitment beacon and you can store all your companions in a small tidy little town where they are easy to find, and crafting is easy to accomplish.

So if you have a few hundred or thousand pounds of gear laying around... that is what these grenades are good for. Load up on gear, summon the bird, get in bird, and pick new settlement to travel to. A lot faster then walking overburdened which I know some of you have done.

Wow, can't believe I didn't think of this. I walked from sanctuary to red rocket with all my crap and that was annoying enough.

if you don't want to take the local leader perk to establish supply lines I guess that works.... or take level 4 of the strong back perk which allows you to fast travel even when over encumbered...... I guess it works.

Sounds useful. Sidestepping any spoilers since I haven't seen them as anything but wrecks yet, is it possible to go down a 'decision-tree' in the game where you lose access to them?

Yes.

I've used the grenades once and found them useless. If you could send the vertibird anywhere then fine, yes you can stop, it but I want to choose exactly where to go.

That use is ok I suppose, but I still prefer sanctuary

Strong Back Level 4 is a no brainer for me. I fast travel encumbered constantly. I think this is needed for anyone playing the game to potential since you are wasting a lot of time traveling to drop off stuff every 10 mins. Collect everything on your way out the door and travel way over loaded.