I garden right upto both my polytunnels, both 15 feet by 25 feet they are about 10 feet apart so with a path up that space I have an outside bed in that space each side of path so I can reach across. I only have to approach polytunnel sides to hoe(with care) or to clean so I just accept walking on soil.I have a path up middle of PT inside so can get to end door without going around. In other locations I have used woodchip for paths but really resent loss of growing space. Can weedkill but as you say mowing close or even hoeing/rotavating would need care. Paving or gravel would be OK if kept back from poly but again loses growing area. I find run off rain and reflected heat and wind shade help immensely with crops on S, E and W sides.
Hope all goes well, enjoy
R