Jim,
Like most items behind the wall, the generally do not require access. A few screws and you should be able to remove the wall. Making that wall more easily removable is up to you. There are no operational concerns to improving it.
Once you get back there and test your converter, should the AC power cord and DC output lines be long enough, you may wish to consider relocating it for easier access to the fuse end. Should you ever accidentally short your hot and ground lines at your battery, even for a moment, or if you connect the leads backwards (cross-polarization), it will blow the fuses in the converter. Most people never have this happen - but it can. I've done it once in 8 years.
Jim