I plan on working this job from the mid May to the end of May.
"５月の中旬から下旬にかけてその仕事をする予定です"
I plan on working this job from the mid May to the end of May.
I plan on working there for about half a month starting mid May.
there = 仕事場
...working at XXX でもいいです。
I intend to do this job from the middle of May to the end of May.
少し変だと思いますけど、これで通じます。
I’m planning to work on that project from mid- to late May.
・I’m planning to work on that project from mid- to late May.
・I’m scheduled to do that work between the middle and the end of May.
・I’ll be doing that job sometime between mid-May and late May.
・I’m expecting to work on it around mid- to late May.
– **mid-May** は「5月中旬」、**late May** は「5月下旬」を表します。日付を細かく言わない場合、この2つの言葉で十分に伝わります。
アメリカ合衆国 
