If you're constantly opening files from certain directories, create aliases for those directories to save time.
To create a directory alias, from the main menu, click Tools > Options, expand Editing and select Global Aliases. Click New, enter a short text snippet that you can easily remember for the alias name, then click OK. Back on the Options dialog, select the new alias, then enter the complete directory path for the alias in the text box on the right. Click OK on the Options dialog.
Now you can use the alias in directory fields on various dialogs in SlickEdit (like File > Open): simply type the alias name and press Ctrl+Space to expand it.