An ac will keep your temps steady but your rh will jump around a bit.

Most consumer grade dehumidifiers actually add some heat to the space, as they generally have the compressor, condensing and evaporating coil in one small package. All AC units will dry the air to an extent, as they cool the air moisture condenses on the coil and drips into a tray. I suggest trying an AC, the type with wheels. If you can vent outside, get the style with two hoses, inside air stays inside, outside air cools the refrigerant. Some will come with a special flange to mount the exhaust hoses in the window. If you use an old window/wall-mount style, just be sure it has a way to drain condensate, and unless you get real creative with ducting, it will be venting the heat into your room. The tent may be cool, but the room would suck to be in.