an auger extension would be cheaper then axles, just put a crazy carpet or any thin plastic sheet through the hole in the floor to the ice to precent freezing/drifting etc
Some times a 5 gallon pail with the bottom cut off will reach the ice. Some guys build a gaff type hook/stick to retrieve fish down the hole,prob not legal but is effective.Of course try not to go through the gills.
Many of these old trailers have a low profile to the ice which is good for fishing but can hang up,the beauty of the trailer is ,it's wired for power,furnace in some,lighting,light towing and easy to move around on the lake to find the sweet spot.I would gut the rest and buildf fold down bunks for over nighting.A carbon monoxide monitor is a must.Just take a cruise out in the country and you can spot old trailers.A friend bought a 16' for a $100 with a furnace and newer tires.