The White Bridge Dilemna

The garden at the Big House is divided in half by a natural creek which runs through it, from front to back.  It is a fabulous feature to have in the garden, and the original landscape installation incorporated two bridges crossing the creek, essentially one at each end of the property.  We have named them brilliantly in my mind, to differentiate one from the other....."The Brown Bridge" is in the wooded garden, and "The White Bridge" is nearer the house, and crosses from the rose garden to the koi ponds.  Since that part of the garden is much more formal, the white bridge is also more "done up" than the brown one.

 The brown bridge was having some real structural issues, so was rebuilt last week, with the new version being virtually identical to the original.  Since this bridge is in shade and only a few feet above the surface of the water, nature takes its toll on even cedar.  Since both bridges are similar in overall design, I've put a photo of the new not yet brown bridge.

The White Bridge is also having some issues, and needs some attention from Tony the fabulous contractor.  Before he begins work, I'm looking for some input from the brilliant individuals who follow this blog.

As you can see from the other two photos, there are hanging baskets which are suspended from the sides of the bridge, which are used for annual color.  They are changed out twice a year, and are equipped with misters from the irrigation system.  They are the "hayrack" type of basket, each 56 inches long, and are lined with moss/cocofiber liners.

Here are the issues I'm trying to correct:
1.  In order to replace the plants, at least one person is standing on a 12-foot stepladder in the creek to work.  This doesn't sound so bad, until you are faced with having to replace the potting medium with giant bags that are being balanced on a non-too-sturdy ladder (on the rocks in the water).  Another person has to lower the plants from above to the planter, since building codes only allow a 4 inch space between balusters.
2.  Because of the constant moisture in the baskets, we've replaced the sideboards once already (the bridge is only ten years old).  We line the back of the baskets with heavy black plastic, but I'm thinking about a new type of container and/or taking the baskets to a metal fabricator to have a new solid back panel installed.

Has anybody out there seen any brilliant designs that would allow for annual color in this situation, without ruining the bridge (and almost killing the gardener)?  I think I've figured out the access issue by exploring the idea of a railing section that can be removed, but I'm not married to that idea.  With reference to the baskets, they can certainly be replaced with something else, but I'm out of ideas.  (The window box type that are sold to hang off deck railings are simply not "high end" enough in appearance, and aren't really in scale with the bridge.

Any ideas, guys?