When using HDMI, sorry, yes, you'll need to use another display to see the home screen so you can step through the player's menu system.
However, if your projector has a composite video input (yellow coax), you might try using that connection. It should show the menu, too.
Once you've set the HDMI output to 720p, it'll stay that way.
Marantz SR7009/7.1.4/FH+TM/DefTech PM1000/LCR+TM amped