I just found out that I cannot train outdoors for the next two months for the 150 km I was planning to attempt in the first week of September. Now I am planning to buy the In'ride 100 trainer from btwin as that's what my budget allows me to buy. Will I still be able to prepare for the 150km on the trainer. What are the advantages and disadvantages? Can anyone give me a training plan and tips. Thanks.
Should be possible, but you are going to need a lot of dedication to sitting for hours on the trainer. You'll also need to put a trainer specific or cheap disposable tire on you bike as trainers wear rear tires fast.
The training you need to do depends on what your level of fitness is, the max distance you can currently ride and the nature of the 180km event (flat or lots of hills) and how you want to ride it (target average speed, how long you plan to take overall, number of stops etc.)
It will be easy to search for and build a training plan with 30-60 minute sessions 3-4 times a week that will increase your overall fitness and strength substantially. This should be your initial priority.
The difficulty will replicating the duration and nature of the long ride. I would not try to replicate the distance of the ride on the trainer, but instead the duration and intensity. Estimate the time duration you will take for the event and plan sessions on the trainer working up to about 75% of that, at your planned intensity.
This is possibly a duplicate of Training for 150 km race in 2 months practicality and plan , so you can still follow the advice in those answers to good effect.
There are some advantages with a trainer because you can control the effort you make on the indoor trainer, and target specific goals with more structure. There are lots of training plans published online. If you use a heart rate (HR) monitor you can set some personalised HR zones and spend time in specific zones to train endurance, power etc. separately as you wish
You can still do shorter, intense rides during the week and longer, steady rides at the weekend, building the distances up week by week like you would have outside.
Tip: using a specific indoor trainer tyre on the trainer because it will not be damaged by the extra heat. Don't then use that indoor tyre outside!
Disadvantages, you need to buy extra stuff and indoor riding can get boring and hot (no airflow). Resistance to pedalling is pretty linear, so estimating speed or distance is not representative of outside, but you can see how well you ride in week one, and build up time, speed, distance week by week.