Hayden,
I must admit that I just scanned this thread and may have missed another response about the Kubota subframe and loader compatibility.
We have a 5240 with a cab and the subframe and the front PTO blower.
The blower works great.
The subframe stays on and works WITH the loader.
The subframe is heavy (1,500 pounds?) and low, increasing stability.
I made up a short steel link to replace the hydraulic cylinder when the blower is off to avoid the blower-mounting "tongue" from drifting down.
We live in the mountain west and our snowfall is way down and the temperatures are way up.
Snowblowers do not handle wet snow well and are overkill for small snowfalls.
Last winter I did not even mount the blower and got a Landpride blade for clearing our long driveway and related areas.
If next winter is similar, I may sell the blower and subframe and just stick with the blade.
Of course, doing that will probably result in the return of 6-foot fluffy drifts

.
Anyway, on the 5240, the subframe and loader ARE compatible.
Your 5740 may be similar.
If anyone is interested, I'll get the tractor out and take a photo to post of the subframe/loader configuration.