This might at first seem a card that's great in solo play but is not well suited to multiplayer. Now, it shines the brightest in solo play (duh), but I think it is excellent even at higher player counts.
Consider that this card does not need to activate every single round to generate a useful profit. Most scenarios last maybe 13-14 turns on average (some are a little longer, some a little shorter). If you drop this on turn 1 and manage to collect on it 60% of the time, you're getting 7-8 resources for the initial investment of 1 card, 1 resource, and 1 action. That's excellent.
And I'd say 60% is a conservative estimate. In most scenarios, there's enough space on the map that you can split up. Indeed, it is very often the correct strategy to do so. Furthermore, you only have to begin your turn alone. The flexible turn order of Arkham Horror really helps here. You can end your turn at the same location as your buddy, and then have your friend go first and move on to the next location. This is an easy way to collect Lone Wolf money while still teaming up with other investigators. My friend used this card as Rex in a 3-player runthrough of the Dunwich campaign; when he had it in play, I estimate he was collecting 80% of the time. If you can do anything near that, this card is excellent.
There are a handful of scenarios (in particular, The Gathering and Essex County Express) in which everyone is necessarily clustered together for most or all of the scenario. In these situations, Lone Wolf is indeed going to be pretty useless. In that case, just mulligan it out of your starting hand. If you draw it later, use it for the agility icon. (Adaptable may also be helpful here.)
Obviously, you need a plan for spending your massive pool of resources. I recommend the skill-boosting permanents (Keen Eye, Streetwise, Scrapper, Higher Education). These cards are already great, but Lone Wolf really takes them to the next level.