As we all experience with our projects - the Devil is in the details. As I started to figure out how to mount all the components for the sensor in the case, I quickly realized that the case that I had chosen was too small. One significant error that I has made was to use a AAA battery pack for sizing when my plan was to use a AA pack.
The case that I had intended to use is 100 x 60 x 25 mm and is shown on the left with MKR 1300 and the AAA battery pack. And below that is the side view of the MKR 1300 and the case. The MKR 1300 comes with extended header pins for use with breadboards and it would barely fit the height of the case, so I was considering cutting off the header pins. The smaller case couldn't accommodate the AA battery pack and would have been a tight fit for the the GPS and other sensors. The nice aspect of the smaller case is that it was a comfortable fit in my hand.
So now I'm going to use a larger case, 100 x 68 x 50 mm, which is shown on the right with the MKR 1300 and the AA battery pack. The good news about this case is that it has screws to attach the lid and also comes with a gasket to make it waterproof (the smaller case cover is a snap fit). It's got twice the height of the small case which means that I don't need to modify the MKR 1300 and it has adequate space for other sensors. The only bad news is that it doesn't fit comfortably in my hand. You can see the height difference in the bottom picture. Functionality wins out.... I can still make use of the smaller case for an indoor sensor or controller (I have that Feather Huzzah board that I got in the 10 Year Challenge 
).
Now I need to figure out where and how to mount the LoRa antenna and other components. I'm initially thinking of putting the temperature sensor inside the case to measure the internal temperature and then later mounting it to the exterior of the case to measure the ambient temperature/humidity/pressure (altitude). I'll probably need to print a housing for it. I think the GPS antenna should be fine inside the case.
I guess I'm putting the cart before the horse.... I think I should hook everything up and verify at least the GPS and temperature sensor are working. I know the LoRa functionality is good on one of the MKR boards so I also need to check the other one. I'm just anxious to get started since there is just over 3 weeks left to finish the project!