Analysis

First of all: it works on mobile.
The plugin is loading on mobile iitc.
It appears with the name "57Cell's Field Planner" in the category "IITC Plugins: Misc".
The menu button "Plan Fields" is shown in the Toolbox ("Info area").
The Planner Window starts very narrow.
- It is possible to resize the window, but it's not very handy on smartphones.
- Might be more comfortable at tablets.
- closing and reopening the window resets it to the narrow default.
The Planner window starts on top of the opened Toolbox ("Info area")
- To work with the map, the user must close the toolbar in the background.
The plan output text area needs much space.
Per default, the layers for links and fields are not active, but they appear in the layers menu and can be activated.
It is possible to select portals.
Touching the preview images of the selected portals in the planner window starts the portal marker animation.
The color selector is working and it is adapting to the touch environment.
All plan types can be generated.
Buttons in the planner window are not made for my fat fingers.
The "More Info" Popup is also very narrow on mobile.

Conclusion

Maybe the output plan textarea could stay hidden and be accessed by a button in a new popup or directly exported to clipboard.
The window position could be saved so the user can put it where they like to and it stays there.
Maybe we could adapt the toolbar button design into the planner window (for mobile), as well as the radiobuttons, they could be dropdown'ish bigger touchable stuff.
Preview images are maybe to much luxury on small mobile devices. They could be deactivated on mobile.
Some of the recommendations in this list are individual taste, so we could make a settings menu to store the preferences.