Going to monitor garage freezer, and have ???

I have found that 30AWG insulated wire-wrapping wire is enough to break some seals. The 30AWG magnet wire will have a smaller outer diameter than that, however, so it might be ok.
I have a couple of ideas here.

1) For the 1-wire connection, maybe use a flat telephone cable wire (or CAT5) and remove the outer covering, exposing just the internal wires and their own sheathing. That way you would have 2 very small diameter wires going through the door seal. I can't believe that this would break the seal.

2) I monitor my hot tub temperature to sense when it drops below a expected minimum - below which, I know that the heater isn't functioning. I suspect that a freezer would have the same approach. If the temp gets higher than the 'normal' temperature swing, then let HS raise an alarm condition. I have mine set a flag, speak every 10 minutes through TTS, and send me an email with the readings until fixed.

3) Again for my hot tub, I wired a DS1820 to a cat5 cable and then encased in a rubber coating that is used to dip tool handles in. I have used this successfully for a couple of years - both in my hot tub and in the lake where I monitor the lake water temperature. It waterproofs it, and also provides good conductivity. It costs only $14 (Canadian) and a 15 ounce can lasts forever! You can find it here . Don't buy the spray, but the can where you 'dip' whatever you want covered. The spray takes too many coats!

I installed my sensor. I used some of the samples I received of adhesive backed 'Flat wire' barely a bump on the freezer edge. I used an old DayQuil package and 'potted' my sensor with automotive 'sensor safe' RTV and mounted inside the freezer near the top protected by the rack.

But now it looks like I have another problem... something is not working, I seem to get erroneous random readings, I am not yet sure the cause. See this post:

I may turn off the freezer for a little while as it may be electrical interference as the flat wire' s adhesive side is actually bare and this is in contact with the metal inside of my freezer.
I have a temp 05 unit and the code that Mitch wrote takes any 255 reading and ignores it. This is obviously a bad reading and should be ignored. I have the same problem with an older humidity sensor. When the temp05 unit receives bad data it read something like 22%. I finally put a counter on the humidity sensor so I could get an idea of how many bad readings it sends and it was dozens. One thing you could do is to simply ignore 255 readings. It appears that all other readings are valid. Did you solder the wire to the temp sensor? I originally tried one of the phone clip style connectors in my freezer and the cold moisture gave me problems so I solder it and the problem cleared.