looking at used JD 3720 or 5045E tractor

[ArlyA]

Yes, easy to use
I have forks, bucket and some homemade stuff

When you "back blade" with a bucket. It doesn't tug against those lock pins?

 

[MtnViewRanch]

I think that you will find that the std skid steer attachments are far more plentiful and usually less money.

Just an FYI.

 

[kennyd]

When you "back blade" with a bucket. It doesn't tug against those lock pins?

It does, but it's a non-issue.
The JDQA system is lightweight, extremely simple, and well proven in the ~30 years it's been around. Any implement you can effectively use on a CUT is readily available in that format.

 

[plastikosmd]

I have over 600’ of gravel driveway that I back drag for maintenance and snow

In nearly 20 yrs of use, no issues, no damage or discernible wear with routine maintenance

It is well designed for the size of the machine