Sway and weight will both be a big problem
As for weight, I (and my Dealer's Asst Service Manager) both feel that a trailer with a loaded weight of over 5000 lbs is probably too much for Colorado towing (even on the plains) because of the big loss of power due to altitude. Even at the relatively low elevation of Loveland (low by Colorado standards anyway), you're already down about 30% from rated sea level torque and HP. Given that a loaded-for-camping 4X4 Tundra will weigh around 5800 lbs (Access Cab) or 6100 lbs (DC)...and the sea level GCWR is 11,800, then the most your trailer really should weigh is around 6000 lbs (AC) or 5700 lbs (DC). That's at sea level. If you derate that sea level towing capacity by 30% for Loveland's altitude (~2000 lbs), then the realistic towing capacity is really about 4000 lbs. Incidentally, if you do tow up into the mountains, the torque really drops off....at 11,000 feet (elevation of the tunnels on I70), torque is a whopping 60% less than at sea level. For the folks who've never done high altitude towing and think the truck should have plenty of power in Colorado, a 60% drop in power due to altitude can roughly be simulated at sea level by removing 5 of the 8 spark plugs.
For mountain towing, my personal experience after 3 towing seasons is 4000 lbs is probably pretty close to an accurate limit (my TrailManor trailer is ~3500 lbs, very low profile, and has a towing length of only 20 feet). If you stay out of the mountains, then 5000 lbs will be tolerable although the tranny will be downshifting on almost every small hill. But since your proposed trailer is realistically going to weigh around 6000 lbs loaded if it's true dry weight is 5400, then I confidently predict you'll be so unhappy towing it in Colorado with your current truck that you'll be trading it for an '07 Tundra (or even a domestic diesel) after just a couple of trips.
Soooo....you really have two choices: Buy the trailer you're thinking of...and spend a bunch of money getting a top end sway control hitch and be really unhappy with the towing performance until you trade up to a more powerful truck...OR...get a much shorter (like around 24 feet), much lighter (like around 3500 lbs empty) trailer and keep your current truck. With a much smaller, much lighter trailer, you won't have to have top end sway control and you'll have enough torque for towing in Colorado.
If you have the Access Cab, you're almost guaranteed to have serious sway control problems with a 30 foot trailer (probably more like a 34 foot trailer in overall exterior length). With the Double Cab, there's a good likelihood of sway control problems anytime you'll be towing with strong crosswinds (which are pretty common here on the front range). The only to combat the problem is with a top end sway control weight distributing hitch...at the minimum a Reese High Performance Dual Cam or, ideally, a Hensley Arrow. The Arrow is virtually guaranteed to ensure you won't have any sway issues under any condition; the problem is a Hensley Arrow hitch sells for around $3000 new. Yep, 3 Grand just for the hitch.
As for weight, I (and my Dealer's Asst Service Manager) both feel that a trailer with a loaded weight of over 5000 lbs is probably too much for Colorado towing (even on the plains) because of the big loss of power due to altitude. Even at the relatively low elevation of Loveland (low by Colorado standards anyway), you're already down about 30% from rated sea level torque and HP. Given that a loaded-for-camping 4X4 Tundra will weigh around 5800 lbs (Access Cab) or 6100 lbs (DC)...and the sea level GCWR is 11,800, then the most your trailer really should weigh is around 6000 lbs (AC) or 5700 lbs (DC). That's at sea level. If you derate that sea level towing capacity by 30% for Loveland's altitude (~2000 lbs), then the realistic towing capacity is really about 4000 lbs. Incidentally, if you do tow up into the mountains, the torque really drops off....at 11,000 feet (elevation of the tunnels on I70), torque is a whopping 60% less than at sea level. For the folks who've never done high altitude towing and think the truck should have plenty of power in Colorado, a 60% drop in power due to altitude can roughly be simulated at sea level by removing 5 of the 8 spark plugs.
For mountain towing, my personal experience after 3 towing seasons is 4000 lbs is probably pretty close to an accurate limit (my TrailManor trailer is ~3500 lbs, very low profile, and has a towing length of only 20 feet). If you stay out of the mountains, then 5000 lbs will be tolerable although the tranny will be downshifting on almost every small hill. But since your proposed trailer is realistically going to weigh around 6000 lbs loaded if it's true dry weight is 5400, then I confidently predict you'll be so unhappy towing it in Colorado with your current truck that you'll be trading it for an '07 Tundra (or even a domestic diesel) after just a couple of trips.
Soooo....you really have two choices: Buy the trailer you're thinking of...and spend a bunch of money getting a top end sway control hitch and be really unhappy with the towing performance until you trade up to a more powerful truck...OR...get a much shorter (like around 24 feet), much lighter (like around 3500 lbs empty) trailer and keep your current truck. With a much smaller, much lighter trailer, you won't have to have top end sway control and you'll have enough torque for towing in Colorado.
