No, the short term is really a subjective thing. I wouldn't get too comfortable with using the dehumidifier, that's all. There are cases where dehumidifiers are a full time 'thing'. Usually, they're used 'inside'; not outside where it's 'exposed' to the elements. (Water freezes and such, as an example.) If a crawlspace is 'part' of a basement, for example, the dehumidifier is on full-time BUT it's not exposed to the elements.
If you're gonna buy a dehumidifier, read the paperwork for them to see that they are for your 'situation' and can handle it. I think the key is to get the gutters fixed/replaced and have the downspout's water routed AWAY from the crawlspace. When you do this, see what happens when it rains. Maybe you'll need a french drain, maybe a drywell, maybe both, and so on. Post up if you need more help or e-mail me directly. (Your post is getting 'buried' already.)