Also Either line up the tents to the main road and have a grid pattern based on that OR make them have their own grid pattern. It's easier to organise troops and know how many you have, easier to rally to defend a part of the camp and generally speeds up any task within the camp to have organised rows.
3 other things you should consider that are v necessary for any camp with this many men around are latrines, kitchen and baggage. Have a dedicated spot for latrines (makes sense that they'd dig their own because they're infamously a spot where people get killed unawares) downwind of the camp.
Second place you definitely need to have is a tent/area of tents specifically for the kitchen. This can be anywhere as long as its not near the latrines. Having it near the commander's tent isn't a bad idea either. A few low tents for the food supplies, a higher frame tent to shelter a cooking fire (think an English barbecue) and for meal preparation (table could be 'foraged') would be perfect. Maybe some animal skinning too.
Thirdly, you need your baggage train. As they aren't expecting organised attack, it'd make sense for the baggage train to be within the camp and protected by it as to deprive any wannabe guerrillas a chance to burn it down or steal from it. This baggage train should contain covered wagons and a few carts for transporting armour, weaponry and the tools to maintain them, food supplies and valuables (stolen or otherwise).
If they were expecting to be attacked by an organised force, the wagons might be positioned around the camp as a defensive wall.