to be honest, I wouldn't do it mobile.
If I do the gel algae wrap, it involves 4 bath sheets on the couch, a foil sheet and a plastic sheet.
I heat the gel up (you could ask your client for a jug of hot water).
I then wipe the excess off with steamed mitts, but before I had a towel cabi I used to have a washing bowl of hot water with 2 flannels in.
its feasible to do, but hard work for you with the set up and clear up time.
i also give the clients a disposable bra and thong to wear.
the gel wrap I decant into 2 small plastic bottles with flip lid, so that I'm not carrying a litre bottle around with me.
Before I apply the gel wrap, I apply an algae exfoliation cream, this again can be removed with hot flannels, but recently I've been applying it thinner and brushing the excess off, but it does make a bit of a mess on the floor (I've got lino at my place so sweep it up when client has gone).